diff --git a/reactos/include/rosrtl/recmutex.h b/reactos/include/rosrtl/recmutex.h
new file mode 100644
index 00000000000..a170d4aed18
--- /dev/null
+++ b/reactos/include/rosrtl/recmutex.h
@@ -0,0 +1,27 @@
+#ifndef _ROSRTL_RECMUTEX_H
+#define _ROSRTL_RECMUTEX_H
+
+typedef struct _RECURSIVE_MUTEX {
+    /* Lock. */
+    FAST_MUTEX Mutex;
+    /* Number of times this object was locked */
+    UINT LockCount;
+    /* CurrentThread */
+    PVOID CurrentThread;  
+    /* Notification event which signals that another thread can take over */
+    KEVENT StateLockedEvent;
+    /* IRQL from spin lock */
+    KIRQL OldIrql;
+    /* Is Locked */
+    BOOLEAN Locked;
+    /* Is reader or writer phase */
+    BOOLEAN Writer;
+    /* Spin lock needed for */
+    KSPIN_LOCK SpinLock;
+} RECURSIVE_MUTEX, *PRECURSIVE_MUTEX;
+
+extern VOID RecursiveMutexInit( PRECURSIVE_MUTEX RecMutex );
+extern UINT RecursiveMutexEnter( PRECURSIVE_MUTEX RecMutex, BOOL ToRead );
+extern VOID RecursiveMutexLeave( PRECURSIVE_MUTEX RecMutex );
+
+#endif/*_ROSRTL_RECMUTEX_H*/
diff --git a/reactos/lib/rosrtl/makefile b/reactos/lib/rosrtl/makefile
index 79bbb9a049e..6fa7b38c5ef 100644
--- a/reactos/lib/rosrtl/makefile
+++ b/reactos/lib/rosrtl/makefile
@@ -1,4 +1,4 @@
-# $Id: makefile,v 1.16 2004/09/15 18:57:01 weiden Exp $
+# $Id: makefile,v 1.17 2004/09/25 21:32:17 arty Exp $
 
 PATH_TO_TOP = ../..
 
@@ -32,6 +32,8 @@ MISC_OBJECTS = \
 FILE_OBJECTS = \
  file/sparse.o
 
+RECMUTEX_OBJECTS = recmutex/recmutex.o
+
 include $(PATH_TO_TOP)/config
 
 include makefile.$(ARCH)
@@ -43,8 +45,8 @@ TARGET_NAME = rosrtl
 TARGET_CFLAGS = -D__USE_W32API -Wall -Werror
 
 TARGET_OBJECTS = $(THREAD_OBJECTS) $(MISC_OBJECTS) $(STRING_OBJECTS) \
-		 $(REGISTRY_OBJECTS) $(FILE_OBJECTS)
- 
+		 $(REGISTRY_OBJECTS) $(FILE_OBJECTS) $(RECMUTEX_OBJECTS)
+
 DEP_OBJECTS = $(TARGET_OBJECTS)
 
 include $(PATH_TO_TOP)/rules.mak
diff --git a/reactos/lib/rosrtl/recmutex/recmutex.c b/reactos/lib/rosrtl/recmutex/recmutex.c
new file mode 100644
index 00000000000..a07d25cf4e9
--- /dev/null
+++ b/reactos/lib/rosrtl/recmutex/recmutex.c
@@ -0,0 +1,84 @@
+#define NTOS_MODE_USER
+#include <ntos.h>
+#include <rosrtl/recmutex.h>
+
+VOID RecursiveMutexInit( PRECURSIVE_MUTEX RecMutex ) {
+    RtlZeroMemory( RecMutex, sizeof(*RecMutex) );
+    KeInitializeSpinLock( &RecMutex->SpinLock );
+    ExInitializeFastMutex( &RecMutex->Mutex );
+    KeInitializeEvent( &RecMutex->StateLockedEvent, 
+		       NotificationEvent, FALSE );    
+}
+
+/* NOTE: When we leave, the FAST_MUTEX must have been released.  The result
+ * is that we always exit in the same irql as entering */
+UINT RecursiveMutexEnter( PRECURSIVE_MUTEX RecMutex, BOOL ToWrite ) {
+    NTSTATUS Status = STATUS_SUCCESS;
+    PVOID CurrentThread = KeGetCurrentThread();
+
+    /* Wait for the previous user to unlock the RecMutex state.  There might be
+     * multiple waiters waiting to change the state.  We need to check each
+     * time we get the event whether somebody still has the state locked */
+
+    if( !RecMutex ) return FALSE;
+
+    if( CurrentThread == RecMutex->CurrentThread || 
+	(!ToWrite && !RecMutex->Writer) ) {
+	RecMutex->LockCount++;
+	return TRUE;
+    }
+
+    if( KeGetCurrentIrql() == PASSIVE_LEVEL ) {
+	ExAcquireFastMutex( &RecMutex->Mutex );
+	RecMutex->OldIrql = PASSIVE_LEVEL;
+	while( RecMutex->Locked ) {
+	    ExReleaseFastMutex( &RecMutex->Mutex );
+	    Status = KeWaitForSingleObject( &RecMutex->StateLockedEvent,
+					    UserRequest,
+					    KernelMode,
+					    FALSE,
+					    NULL );
+	    ExAcquireFastMutex( &RecMutex->Mutex );
+	    if( Status == STATUS_SUCCESS ) break;
+	}
+	RecMutex->Locked = TRUE;
+	RecMutex->Writer = ToWrite;
+	RecMutex->CurrentThread = CurrentThread;
+	RecMutex->LockCount++;
+	ExReleaseFastMutex( &RecMutex->Mutex );
+    } else {
+	KeAcquireSpinLock( &RecMutex->SpinLock, &RecMutex->OldIrql );
+	RecMutex->Locked = TRUE;
+	RecMutex->Writer = ToWrite;
+	RecMutex->CurrentThread = CurrentThread;
+	RecMutex->LockCount++;
+    }
+
+    return TRUE;
+}
+
+VOID RecursiveMutexLeave( PRECURSIVE_MUTEX RecMutex ) {
+    if( RecMutex->LockCount == 0 ) {
+	return;
+    } else
+	RecMutex->LockCount--;
+
+    if( !RecMutex->LockCount ) {
+	RecMutex->CurrentThread = NULL;
+	if( RecMutex->OldIrql == PASSIVE_LEVEL ) {
+	    ExAcquireFastMutex( &RecMutex->Mutex );
+	    RecMutex->Locked = FALSE;
+	    RecMutex->Writer = FALSE;
+	    ExReleaseFastMutex( &RecMutex->Mutex );
+	} else {
+	    RecMutex->Locked = FALSE;
+	    RecMutex->Writer = FALSE;
+	    KeReleaseSpinLock( &RecMutex->SpinLock, RecMutex->OldIrql );
+	}
+
+	RecMutex->OldIrql = PASSIVE_LEVEL;
+	KePulseEvent( &RecMutex->StateLockedEvent, IO_NETWORK_INCREMENT, 
+		      FALSE );
+    }
+}
+