diff -Naur a/asmcomp/i386/proc.ml b/asmcomp/i386/proc.ml
--- a/asmcomp/i386/proc.ml	2007-02-09 13:31:14.000000000 +0000
+++ b/asmcomp/i386/proc.ml	2016-06-15 20:58:18.990419400 +0100
@@ -181,7 +181,7 @@
 (* Calling the assembler *)
 
 let assemble_file infile outfile =
-  Ccomp.command ("as -o " ^ Filename.quote outfile ^ " " ^ Filename.quote infile)
+  Ccomp.command (Printf.sprintf "%sas -o %s %s" (if Config.system = "mingw" then "i686-w64-mingw32-" else "") (Filename.quote outfile) (Filename.quote infile))
 
 open Clflags;;
 open Config;;
diff -Naur a/config/Makefile.mingw b/config/Makefile.mingw
--- a/config/Makefile.mingw	2007-03-01 14:48:53.000000000 +0000
+++ b/config/Makefile.mingw	2016-06-15 21:35:15.833922900 +0100
@@ -75,7 +75,7 @@
 ########## Configuration for the bytecode compiler
 
 ### Which C compiler to use for the bytecode interpreter.
-BYTECC=gcc -mno-cygwin
+BYTECC=i686-w64-mingw32-gcc
 
 ### Additional compile-time options for $(BYTECC).  (For static linking.)
 BYTECCCOMPOPTS=-O -mms-bitfields -Wall -Wno-unused
@@ -98,20 +98,20 @@
 #ml let mkexe out files opts = Printf.sprintf "%s -o %s %s %s" bytecc out opts files;;
 
 ### How to build a DLL
-MKDLL=$(BYTECC) -shared -o $(1) -Wl,--out-implib,$(2) $(3)
-#ml let mkdll out implib files opts = Printf.sprintf "%s -shared -o %s -Wl,--out-implib,%s %s %s" bytecc out implib files opts;;
+MKDLL=$(BYTECC) -static-libgcc -shared -o $(1) -Wl,--out-implib,$(2) $(3)
+#ml let mkdll out implib files opts = Printf.sprintf "%s -static-libgcc -shared -o %s -Wl,--out-implib,%s %s %s" bytecc out implib files opts;;
 
 ### How to build a static library
-MKLIB=rm -f $(1); ar rcs $(1) $(2)
-#ml let mklib out files opts = Printf.sprintf "rm -f %s && ar rcs %s %s %s" out opts out files;;
+MKLIB=rm -f $(1); i686-w64-mingw32-ar rcs $(1) $(2)
+#ml let mklib out files opts = Printf.sprintf "rm -f %s && i686-w64-mingw32-ar rcs %s %s %s" out opts out files;;
 
 ### Canonicalize the name of a system library
 SYSLIB=-l$(1)
 #ml let syslib x = "-l"^x;;
 
 ### The ranlib command
-RANLIB=ranlib
-RANLIBCMD=ranlib
+RANLIB=i686-w64-mingw32-ranlib
+RANLIBCMD=i686-w64-mingw32-ranlib
 
 ############# Configuration for the native-code compiler
 
@@ -134,7 +134,7 @@
 NATIVECCLINKOPTS=
 
 ### Build partially-linked object file
-PARTIALLD=ld -r $(NATIVECCLINKOPTS)
+PARTIALLD=i686-w64-mingw32-ld -r $(NATIVECCLINKOPTS)
 PACKLD=$(PARTIALLD) -o #there must be a space after this '-o'
 
 ############# Configuration for the contributed libraries
diff -Naur a/utils/ccomp.ml b/utils/ccomp.ml
--- a/utils/ccomp.ml	2007-11-10 12:23:37.000000000 +0000
+++ b/utils/ccomp.ml	2016-06-15 16:11:52.315441000 +0100
@@ -70,7 +70,8 @@
                              quoted_archive (quote_files file_list))
   | _ ->
       let r1 =
-        command(Printf.sprintf "ar rc %s %s"
+        command(Printf.sprintf "%sar rc %s %s"
+                (if Config.system = "mingw" then "i686-w64-mingw32-" else "")
                 quoted_archive (quote_files file_list)) in
       if r1 <> 0 || String.length Config.ranlib = 0
       then r1
diff -Naur a/win32caml/Makefile b/win32caml/Makefile
--- a/win32caml/Makefile	2006-10-03 12:53:57.000000000 +0100
+++ b/win32caml/Makefile	2016-06-15 16:11:52.331066000 +0100
@@ -40,7 +40,7 @@
 	rm -f ocaml.res
 endif
 ifeq ($(TOOLCHAIN),mingw)
-	windres -i ocaml.rc -o $@
+	i686-w64-mingw32-windres -i ocaml.rc -o $@
 endif
 
 $(OBJS): inria.h inriares.h history.h editbuffer.h