diff --git a/src/CHANGELOG b/src/CHANGELOG
index d331e3497..6cc75ee7d 100644
--- a/src/CHANGELOG
+++ b/src/CHANGELOG
@@ -74,6 +74,9 @@ ECL 0.9i
    not mean that everything has been implemented, but it makes the implemented
    options accessible.
 
+ - Included support for multithreading under Windows/Cygwin (Thanks to Arthur
+   Smyles for pointing out the differences from Linux's pthreads)
+
 * Errors fixed:
 
  - The intermediate output of the compiler is written in the directory in which
diff --git a/src/aclocal.m4 b/src/aclocal.m4
index a6c73f6d7..f6b1ca940 100644
--- a/src/aclocal.m4
+++ b/src/aclocal.m4
@@ -231,6 +231,8 @@ case "${host_os}" in
 		thehost='cygwin'
 		shared='yes'
 		THREAD_OBJ=''
+		THREAD_CFLAGS='-D_THREAD_SAFE'
+		THREAD_LIBS='-lpthread'
 		SHARED_LDFLAGS="-shared ${LDFLAGS}"
 		BUNDLE_LDFLAGS="-shared ${LDFLAGS}"
 		SHAREDPREFIX=''
diff --git a/src/configure b/src/configure
index 96af79bcb..370537f15 100755
--- a/src/configure
+++ b/src/configure
@@ -3556,6 +3556,8 @@ case "${host_os}" in
 		thehost='cygwin'
 		shared='yes'
 		THREAD_OBJ=''
+		THREAD_CFLAGS='-D_THREAD_SAFE'
+		THREAD_LIBS='-lpthread'
 		SHARED_LDFLAGS="-shared ${LDFLAGS}"
 		BUNDLE_LDFLAGS="-shared ${LDFLAGS}"
 		SHAREDPREFIX=''
diff --git a/src/h/config.h.in b/src/h/config.h.in
index 6233fbe00..1f8b17b7d 100644
--- a/src/h/config.h.in
+++ b/src/h/config.h.in
@@ -300,4 +300,11 @@ typedef unsigned @CL_FIXNUM_TYPE@ cl_hashkey;
 #  define PTHREAD_MUTEX_RECURSIVE_NP PTHREAD_MUTEX_RECURSIVE
 #  define PTHREAD_MUTEX_NORMAL_NP PTHREAD_MUTEX_NORMAL
 # endif
+# if defined(cygwin)
+#  define PTHREAD_MUTEX_FAST_NP PTHREAD_MUTEX_NORMAL
+#  define PTHREAD_MUTEX_RECURSIVE_NP PTHREAD_MUTEX_RECURSIVE
+#  define PTHREAD_MUTEX_ERRORCHECK_NP PTHREAD_MUTEX_ERRORCHECK
+#  define PTHREAD_MUTEX_TIMED_NP PTHREAD_MUTEX_NORMAL
+#  define PTHREAD_MUTEX_ADAPTIVE_NP PTHREAD_MUTEX_NORMAL
+# endif
 #endif