diff --git a/src/frontend/com_hardcopy.c b/src/frontend/com_hardcopy.c
index bde585d01..131f0e6f4 100644
--- a/src/frontend/com_hardcopy.c
+++ b/src/frontend/com_hardcopy.c
@@ -1,5 +1,4 @@
 #include "ngspice/config.h"
-#include <stdio.h>
 
 #include "ngspice/ngspice.h"
 #include "ngspice/defines.h"
diff --git a/src/frontend/numparam/spicenum.c b/src/frontend/numparam/spicenum.c
index 58f488414..5010c6470 100644
--- a/src/frontend/numparam/spicenum.c
+++ b/src/frontend/numparam/spicenum.c
@@ -21,11 +21,10 @@ Todo:
   add support for nested .if .elsif .else .endif controls.
 */
 
-#include <stdio.h>
+#include "ngspice/ngspice.h"
 
 #include "general.h"
 #include "numparam.h"
-#include "ngspice/ngspice.h"
 
 #include "ngspice/fteext.h" /* controlled_exit() */
 
diff --git a/src/frontend/numparam/xpressn.c b/src/frontend/numparam/xpressn.c
index 02324daca..a365a6ee0 100644
--- a/src/frontend/numparam/xpressn.c
+++ b/src/frontend/numparam/xpressn.c
@@ -4,12 +4,10 @@
    Free software under the terms of the GNU Lesser General Public License
 */
 
-#include <stdio.h>                /* for function message() only. */
-#include <stdarg.h>
+#include "ngspice/ngspice.h"
 
 #include "general.h"
 #include "numparam.h"
-#include "ngspice/ngspice.h"
 #include "ngspice/cpdefs.h"
 #include "ngspice/ftedefs.h"
 #include "ngspice/dvec.h"
diff --git a/src/frontend/trannoise/1-f-code.c b/src/frontend/trannoise/1-f-code.c
index a0bff6de5..9db935714 100644
--- a/src/frontend/trannoise/1-f-code.c
+++ b/src/frontend/trannoise/1-f-code.c
@@ -7,11 +7,6 @@
  Volume 83,  Issue 5,  May 1995 Page(s):802 - 827
 */
 
-#include <math.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <stdarg.h>                     // var. argumente
 #include "ngspice/ngspice.h"
 #include "ngspice/cpextern.h"
 #include "ngspice/cktdefs.h"
diff --git a/src/frontend/trannoise/FastNorm3.c b/src/frontend/trannoise/FastNorm3.c
index 4339577f7..7104512db 100644
--- a/src/frontend/trannoise/FastNorm3.c
+++ b/src/frontend/trannoise/FastNorm3.c
@@ -61,10 +61,10 @@ Normal  (a very fast routine)
 */
 
 /* ----------------- inclusions and some definitions ------------ */
-#include <math.h>
 #ifndef NOSPICE
 #include "ngspice/ngspice.h"
 #endif
+#include <math.h>
 #include "ngspice/FastNorm3.h"
 
 
diff --git a/src/frontend/trannoise/wallace.c b/src/frontend/trannoise/wallace.c
index 6bbdf10a3..ff5a9118c 100644
--- a/src/frontend/trannoise/wallace.c
+++ b/src/frontend/trannoise/wallace.c
@@ -4,8 +4,13 @@
 
 //#define FASTNORM_ORIG
 
-#include <stdio.h>
-#include <stdlib.h>
+#ifdef HasMain
+#include <sys/timeb.h>
+#else
+#ifndef NOSPICE
+#include "ngspice/ngspice.h"
+#endif
+#endif
 #ifdef _MSC_VER
 #include <process.h>
 #define getpid _getpid
@@ -16,14 +21,6 @@
 #include "ngspice/wallace.h"
 #include "ngspice/FastNorm3.h"
 
-#ifdef HasMain
-#include <sys/timeb.h>
-#else
-#ifndef NOSPICE
-#include "ngspice/ngspice.h"
-#endif
-#endif
-
 #define POOLSIZE 4096
 #define LPOOLSIZE 12
 #define NOTRANS 3 /* number of (dual) transformations */
diff --git a/src/frontend/variable.c b/src/frontend/variable.c
index 2e577c7d9..7be9792a0 100644
--- a/src/frontend/variable.c
+++ b/src/frontend/variable.c
@@ -4,9 +4,6 @@ Author: 1985 Wayne A. Christopher, U. C. Berkeley CAD Group
 **********/
 
 #include "ngspice/config.h"
-#include <string.h>
-#include <stdio.h>
-#include <stdlib.h>
 
 #include "ngspice/ngspice.h"
 #include "ngspice/bool.h"
diff --git a/src/spicelib/devices/hisim2/hsm2acld.c b/src/spicelib/devices/hisim2/hsm2acld.c
index b31cb88b7..976d146f5 100644
--- a/src/spicelib/devices/hisim2/hsm2acld.c
+++ b/src/spicelib/devices/hisim2/hsm2acld.c
@@ -13,7 +13,6 @@
                 Semiconductor Technology Academic Research Center (STARC)
 ***********************************************************************/
 
-#include <stdio.h>
 #include "ngspice/ngspice.h"
 #include "ngspice/cktdefs.h"
 #include "ngspice/sperror.h"
diff --git a/src/spicelib/devices/hisim2/hsm2eval.c b/src/spicelib/devices/hisim2/hsm2eval.c
index a6e96b395..e2acfcd68 100644
--- a/src/spicelib/devices/hisim2/hsm2eval.c
+++ b/src/spicelib/devices/hisim2/hsm2eval.c
@@ -130,17 +130,12 @@ using the HiSIM2 standard.
 /*---------------------------------------------------*
 * Header files.
 *-----------------*/
-#include <stdlib.h>
-#include <stdio.h>
-#include <math.h>
-#include <float.h>
+#include "ngspice/ngspice.h"
 #ifdef __STDC__
 /* #include <ieeefp.h> */
 #endif
 #include "ngspice/cktdefs.h"
 
-#include "ngspice/ngspice.h"
-
 /*-----------------------------------*
 * HiSIM macros
 *-----------------*/
diff --git a/src/spicelib/devices/hisim2/hsm2ld.c b/src/spicelib/devices/hisim2/hsm2ld.c
index 36b752f95..bf46f63ee 100644
--- a/src/spicelib/devices/hisim2/hsm2ld.c
+++ b/src/spicelib/devices/hisim2/hsm2ld.c
@@ -13,7 +13,6 @@
                 Semiconductor Technology Academic Research Center (STARC)
 ***********************************************************************/
 
-#include <stdio.h>
 #include "ngspice/ngspice.h"
 #include "ngspice/cktdefs.h"
 #include "hsm2def.h"
diff --git a/src/spicelib/parser/inppas1.c b/src/spicelib/parser/inppas1.c
index 9b508e610..20b97ad03 100644
--- a/src/spicelib/parser/inppas1.c
+++ b/src/spicelib/parser/inppas1.c
@@ -3,8 +3,6 @@ Copyright 1990 Regents of the University of California.  All rights reserved.
 Author: 1985 Thomas L. Quarles
 **********/
 
-#include <stdio.h>
-
 #include "ngspice/config.h"
 #include "ngspice/ngspice.h"
 
diff --git a/src/xspice/evt/evtbackup.c b/src/xspice/evt/evtbackup.c
index e2c2ecab2..fbe2988ea 100644
--- a/src/xspice/evt/evtbackup.c
+++ b/src/xspice/evt/evtbackup.c
@@ -40,7 +40,6 @@ NON-STANDARD FEATURES
 
 
 /*=== INCLUDE FILES ===*/
-#include <stdio.h>
 #include "ngspice/ngspice.h"
 
 #include "ngspice/cktdefs.h"
diff --git a/src/xspice/evt/evtdeque.c b/src/xspice/evt/evtdeque.c
index fa8b5a261..450e10ae4 100644
--- a/src/xspice/evt/evtdeque.c
+++ b/src/xspice/evt/evtdeque.c
@@ -38,8 +38,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include <stdio.h>
-
 #include "ngspice/ngspice.h"
 
 #include "ngspice/cktdefs.h"
diff --git a/src/xspice/evt/evtdump.c b/src/xspice/evt/evtdump.c
index af8173372..b271e3131 100644
--- a/src/xspice/evt/evtdump.c
+++ b/src/xspice/evt/evtdump.c
@@ -39,9 +39,6 @@ NON-STANDARD FEATURES
 ============================================================================*/
 
 
-#include <stdio.h>
-#include <string.h>
-
 #include "ngspice/ngspice.h"
 //#include "misc.h"
 
diff --git a/src/xspice/evt/evtinit.c b/src/xspice/evt/evtinit.c
index 539f49211..7cd456066 100644
--- a/src/xspice/evt/evtinit.c
+++ b/src/xspice/evt/evtinit.c
@@ -40,8 +40,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include  <string.h>
-#include  <stdio.h>
 #include "ngspice/ngspice.h"
 #include  "ngspice/cktdefs.h"
 //#include  "util.h"
diff --git a/src/xspice/evt/evtiter.c b/src/xspice/evt/evtiter.c
index 7f1ac21e5..ee774225f 100644
--- a/src/xspice/evt/evtiter.c
+++ b/src/xspice/evt/evtiter.c
@@ -38,9 +38,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include <stdio.h>
-#include <string.h>
-
 #include "ngspice/ngspice.h"
 //#include "misc.h"
 #include "ngspice/cktdefs.h"
diff --git a/src/xspice/evt/evtload.c b/src/xspice/evt/evtload.c
index ad27cbf3f..d4ace6f19 100644
--- a/src/xspice/evt/evtload.c
+++ b/src/xspice/evt/evtload.c
@@ -39,8 +39,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include <stdio.h>
-
 #include "ngspice/ngspice.h"
 #include "ngspice/cktdefs.h"
 //#include "util.h"
diff --git a/src/xspice/evt/evtnext_time.c b/src/xspice/evt/evtnext_time.c
index 771a66a6e..e2ba382e8 100644
--- a/src/xspice/evt/evtnext_time.c
+++ b/src/xspice/evt/evtnext_time.c
@@ -38,8 +38,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include <stdio.h>
-
 #include "ngspice/ngspice.h"
 #include "ngspice/cktdefs.h"
 //#include "util.h"
diff --git a/src/xspice/evt/evtop.c b/src/xspice/evt/evtop.c
index dd1117ff3..d2c272b37 100644
--- a/src/xspice/evt/evtop.c
+++ b/src/xspice/evt/evtop.c
@@ -40,7 +40,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include <stdio.h>
 #include "ngspice/ngspice.h"
 #include "ngspice/cktdefs.h"
 //#include "util.h"
diff --git a/src/xspice/evt/evtplot.c b/src/xspice/evt/evtplot.c
index 665bc4e7b..c9d244008 100644
--- a/src/xspice/evt/evtplot.c
+++ b/src/xspice/evt/evtplot.c
@@ -37,9 +37,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include <stdio.h>
-#include <string.h>
-
 #include "ngspice/ngspice.h"
 //nclude "misc.h"
 #include "ngspice/evt.h"
diff --git a/src/xspice/evt/evtprint.c b/src/xspice/evt/evtprint.c
index b40837063..7fccc41aa 100644
--- a/src/xspice/evt/evtprint.c
+++ b/src/xspice/evt/evtprint.c
@@ -39,9 +39,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include <stdio.h>
-#include <string.h>
-
 #include "ngspice/ngspice.h"
 
 #include "ngspice/cpstd.h"
diff --git a/src/xspice/evt/evtqueue.c b/src/xspice/evt/evtqueue.c
index 40b9152fd..c3725e005 100644
--- a/src/xspice/evt/evtqueue.c
+++ b/src/xspice/evt/evtqueue.c
@@ -50,8 +50,6 @@ NON-STANDARD FEATURES
 ============================================================================*/
 
 
-#include <stdio.h>
-
 #include "ngspice/ngspice.h"
 #include "ngspice/cktdefs.h"
 //#include "util.h"
diff --git a/src/xspice/evt/evtsetup.c b/src/xspice/evt/evtsetup.c
index 3edb34034..d078ad549 100644
--- a/src/xspice/evt/evtsetup.c
+++ b/src/xspice/evt/evtsetup.c
@@ -40,9 +40,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include <stdio.h>
-#include <string.h>
-
 #include "ngspice/ngspice.h"
 //#include "misc.h"
 
diff --git a/src/xspice/evt/evttermi.c b/src/xspice/evt/evttermi.c
index bac2d66af..ab7429b8e 100644
--- a/src/xspice/evt/evttermi.c
+++ b/src/xspice/evt/evttermi.c
@@ -49,8 +49,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include <stdio.h>
-
 #include "ngspice/ngspice.h"
 //#include "misc.h"
 
diff --git a/src/xspice/mif/mifdelete.c b/src/xspice/mif/mifdelete.c
index 80bd99b10..fd64c8be3 100644
--- a/src/xspice/mif/mifdelete.c
+++ b/src/xspice/mif/mifdelete.c
@@ -38,7 +38,6 @@ NON-STANDARD FEATURES
 
 ============================================================================*/
 
-#include <stdio.h>
 #include "ngspice/ngspice.h"
 #include "ngspice/sperror.h"
 #include "ngspice/gendefs.h"