diff --git a/reactos/include/internal/service.h b/reactos/include/internal/service.h
index 627ee35209d..70160493379 100644
--- a/reactos/include/internal/service.h
+++ b/reactos/include/internal/service.h
@@ -9,5 +9,29 @@ typedef struct _SERVICE_TABLE
    unsigned long  Function;
 } SERVICE_TABLE, *PSERVICE_TABLE;
 
+#pragma pack(1)
+
+// System Service Dispatch Table
+typedef struct t_SSDT {
+                ULONG           SysCallPtr;
+} SSDT, *PSSDT;
+
+// System Service Parameters Table
+typedef struct t_SSPT   {
+                unsigned int    ParamBytes;
+} SSPT, *PSSPT;
+
+typedef struct t_KeServiceDescriptorTableEntry {
+                PSSDT               pSSDT;
+                unsigned long*      ServiceCounterTable;
+                unsigned int        NumberOfServices;
+                PSSPT               pSSPT;
+
+} KE_SERVICE_DESCRIPTOR_TABLE_ENTRY, *PKE_SERVICE_DESCRIPTOR_TABLE_ENTRY;
+
+#pragma pack()
+
+NTSTATUS KeAddSystemServiceTable( int SSDTindex, PSSDT pSSDT, PSSPT pSSPT, ULONG* SyscallsCountTable );
+
 #endif