diff --git a/dlls/ntdll/nt.c b/dlls/ntdll/nt.c
index 7560adfe050..b1de3fe9969 100644
--- a/dlls/ntdll/nt.c
+++ b/dlls/ntdll/nt.c
@@ -658,15 +658,18 @@ NTSTATUS WINAPI NtQuerySystemInformation(
         break;
     case SystemTimeOfDayInformation:
         {
-            SYSTEM_TIMEOFDAY_INFORMATION* sti = (SYSTEM_TIMEOFDAY_INFORMATION*)SystemInformation;
-            if (Length >= sizeof(*sti))
+            SYSTEM_TIMEOFDAY_INFORMATION sti;
+
+            memset(&sti, 0 , sizeof(sti));
+
+            /* liKeSystemTime, liExpTimeZoneBias, uCurrentTimeZoneId */
+            sti.liKeBootTime.QuadPart = boottime;
+
+            if (Length <= sizeof(sti))
             {
-                sti->liKeBootTime.QuadPart = boottime;
-                sti->liKeSystemTime.QuadPart = 0; /* FIXME */
-                sti->liExpTimeZoneBias.QuadPart  = 0; /* FIXME */
-                sti->uCurrentTimeZoneId = 0; /* FIXME */
-                sti->dwReserved = 0;
-                len = sizeof(*sti);
+                len = Length;
+                if (!SystemInformation) ret = STATUS_ACCESS_VIOLATION;
+                else memcpy( SystemInformation, &sti, Length);
             }
             else ret = STATUS_INFO_LENGTH_MISMATCH;
         }
diff --git a/dlls/ntdll/tests/info.c b/dlls/ntdll/tests/info.c
index acf768a58e2..085f7f0a066 100644
--- a/dlls/ntdll/tests/info.c
+++ b/dlls/ntdll/tests/info.c
@@ -80,7 +80,7 @@ static void test_query_basic()
     trace("Check with correct parameters\n");
     status = pNtQuerySystemInformation(SystemBasicInformation, &sbi, sizeof(sbi), &ReturnLength);
     ok( status == STATUS_SUCCESS, "Expected STATUS_SUCCESS, got %08lx\n", status);
-    ok( sizeof(sbi) == ReturnLength, "Inconsistent length (%08x) <-> (%ld)\n", sizeof(sbi), ReturnLength);
+    ok( sizeof(sbi) == ReturnLength, "Inconsistent length (%d) <-> (%ld)\n", sizeof(sbi), ReturnLength);
 
     /* Check if we have some return values */
     trace("Number of Processors : %d\n", sbi.NumberOfProcessors);
@@ -95,13 +95,93 @@ static void test_query_cpu()
 
     status = pNtQuerySystemInformation(SystemCpuInformation, &sci, sizeof(sci), &ReturnLength);
     ok( status == STATUS_SUCCESS, "Expected STATUS_SUCCESS, got %08lx\n", status);
-    ok( sizeof(sci) == ReturnLength, "Inconsistent length (%08x) <-> (%ld)\n", sizeof(sci), ReturnLength);
+    ok( sizeof(sci) == ReturnLength, "Inconsistent length (%d) <-> (%ld)\n", sizeof(sci), ReturnLength);
                                                                                                                        
     /* Check if we have some return values */
     trace("Processor FeatureSet : %08lx\n", sci.FeatureSet);
     ok( sci.FeatureSet != 0, "Expected some features for this processor, got %08lx\n", sci.FeatureSet);
 }
 
+static void test_query_timeofday()
+{
+    DWORD status;
+    ULONG ReturnLength;
+    int isnt = 0;
+
+    /* Copy of our winternl.h structure turned into a private one */
+    typedef struct _SYSTEM_TIMEOFDAY_INFORMATION_PRIVATE {
+        LARGE_INTEGER liKeBootTime;
+        LARGE_INTEGER liKeSystemTime;
+        LARGE_INTEGER liExpTimeZoneBias;
+        ULONG uCurrentTimeZoneId;
+        DWORD dwUnknown1[5];
+    } SYSTEM_TIMEOFDAY_INFORMATION_PRIVATE, *PSYSTEM_TIMEOFDAY_INFORMATION_PRIVATE;
+
+    SYSTEM_TIMEOFDAY_INFORMATION_PRIVATE sti;
+  
+    /*  The structsize for NT (32 bytes) and Win2K/XP (48 bytes) differ.
+     *
+     *  Windows 2000 and XP return STATUS_INFO_LENGTH_MISMATCH if the given buffer size is greater
+     *  then 48 and 0 otherwise
+     *  Windows NT returns STATUS_INFO_LENGTH_MISMATCH when the given buffer size is not correct
+     *  and 0 otherwise
+     *
+     *  Windows 2000 and XP copy the given buffer size into the provided buffer, if the return code is STATUS_SUCCESS
+     *  NT only fills the buffer if the return code is STATUS_SUCCESS
+     *
+    */
+
+    status = pNtQuerySystemInformation(SystemTimeOfDayInformation, &sti, sizeof(sti), &ReturnLength);
+    isnt = ( status == STATUS_INFO_LENGTH_MISMATCH);
+
+    if (isnt)
+    {
+        trace("Windows version is NT, we have to cater for differences with W2K/WinXP\n");
+ 
+        status = pNtQuerySystemInformation(SystemTimeOfDayInformation, &sti, 0, &ReturnLength);
+        ok( status == STATUS_INFO_LENGTH_MISMATCH, "Expected STATUS_INFO_LENGTH_MISMATCH, got %08lx\n", status);
+        ok( 0 == ReturnLength, "ReturnLength should be 0, it is (%ld)\n", ReturnLength);
+
+        sti.uCurrentTimeZoneId = 0xdeadbeef;
+        status = pNtQuerySystemInformation(SystemTimeOfDayInformation, &sti, 28, &ReturnLength);
+        ok( 0xdeadbeef == sti.uCurrentTimeZoneId, "This part of the buffer should not have been filled\n");
+
+        status = pNtQuerySystemInformation(SystemTimeOfDayInformation, &sti, 32, &ReturnLength);
+        ok( status == STATUS_SUCCESS, "Expected STATUS_SUCCESS, got %08lx\n", status);
+        ok( 32 == ReturnLength, "ReturnLength should be 0, it is (%ld)\n", ReturnLength);
+    }
+    else
+    {
+
+        status = pNtQuerySystemInformation(SystemTimeOfDayInformation, &sti, 0, &ReturnLength);
+        ok( status == STATUS_SUCCESS, "Expected STATUS_SUCCESS, got %08lx\n", status);
+        ok( 0 == ReturnLength, "ReturnLength should be 0, it is (%ld)\n", ReturnLength);
+
+        sti.uCurrentTimeZoneId = 0xdeadbeef;
+        status = pNtQuerySystemInformation(SystemTimeOfDayInformation, &sti, 24, &ReturnLength);
+        ok( status == STATUS_SUCCESS, "Expected STATUS_SUCCESS, got %08lx\n", status);
+        ok( 24 == ReturnLength, "ReturnLength should be 24, it is (%ld)\n", ReturnLength);
+        ok( 0xdeadbeef == sti.uCurrentTimeZoneId, "This part of the buffer should not have been filled\n");
+    
+        sti.uCurrentTimeZoneId = 0xdeadbeef;
+        status = pNtQuerySystemInformation(SystemTimeOfDayInformation, &sti, 32, &ReturnLength);
+        ok( status == STATUS_SUCCESS, "Expected STATUS_SUCCESS, got %08lx\n", status);
+        ok( 32 == ReturnLength, "ReturnLength should be 32, it is (%ld)\n", ReturnLength);
+        ok( 0xdeadbeef != sti.uCurrentTimeZoneId, "Buffer should have been partially filled\n");
+    
+        status = pNtQuerySystemInformation(SystemTimeOfDayInformation, &sti, 49, &ReturnLength);
+        ok( status == STATUS_INFO_LENGTH_MISMATCH, "Expected STATUS_INFO_LENGTH_MISMATCH, got %08lx\n", status);
+        ok( 0 == ReturnLength, "ReturnLength should be 0, it is (%ld)\n", ReturnLength);
+    
+        status = pNtQuerySystemInformation(SystemTimeOfDayInformation, &sti, sizeof(sti), &ReturnLength);
+        ok( status == STATUS_SUCCESS, "Expected STATUS_SUCCESS, got %08lx\n", status);
+        ok( sizeof(sti) == ReturnLength, "Inconsistent length (%d) <-> (%ld)\n", sizeof(sti), ReturnLength);
+    }
+
+    /* Check if we have some return values */
+    trace("uCurrentTimeZoneId : (%ld)\n", sti.uCurrentTimeZoneId);
+}
+
 static void test_query_process()
 {
     DWORD status;
@@ -250,6 +330,10 @@ START_TEST(info)
     trace("Starting test_query_cpu()\n");
     test_query_cpu();
 
+    /* 0x3 SystemCpuInformation */
+    trace("Starting test_query_timeofday()\n");
+    test_query_timeofday();
+
     /* 0x5 SystemProcessInformation */
     trace("Starting test_query_process()\n");
     test_query_process();
diff --git a/include/winternl.h b/include/winternl.h
index 0509c7039a7..ade75ad51c2 100644
--- a/include/winternl.h
+++ b/include/winternl.h
@@ -977,7 +977,7 @@ typedef struct _SYSTEM_TIMEOFDAY_INFORMATION {
     LARGE_INTEGER liKeSystemTime;
     LARGE_INTEGER liExpTimeZoneBias;
     ULONG uCurrentTimeZoneId;
-    DWORD dwReserved;
+    DWORD dwUnknown1[5];
 #else
     BYTE Reserved1[48];
 #endif