diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index ebc9c185..0a2d589d 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -2851,7 +2851,9 @@ size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
         if ((cctx->pledgedSrcSizePlusOne-1) <= ZSTDMT_JOBSIZE_MIN)
             params.nbThreads = 1; /* do not invoke multi-threading when src size is too small */
         if (params.nbThreads > 1) {
-            if (cctx->mtctx == NULL || cctx->appliedParams.nbThreads != params.nbThreads) {
+            if (cctx->mtctx == NULL || (params.nbThreads != ZSTDMT_getNbThreads(cctx->mtctx))) {
+                DEBUGLOG(4, "ZSTD_compress_generic: creating new mtctx for nbThreads=%u (previous: %u)",
+                            params.nbThreads, ZSTDMT_getNbThreads(cctx->mtctx));
                 ZSTDMT_freeCCtx(cctx->mtctx);
                 cctx->mtctx = ZSTDMT_createCCtx_advanced(params.nbThreads, cctx->customMem);
                 if (cctx->mtctx == NULL) return ERROR(memory_allocation);
diff --git a/lib/compress/zstdmt_compress.c b/lib/compress/zstdmt_compress.c
index a5e996d3..659992f3 100644
--- a/lib/compress/zstdmt_compress.c
+++ b/lib/compress/zstdmt_compress.c
@@ -459,6 +459,15 @@ size_t ZSTDMT_CCtxParam_setNbThreads(ZSTD_CCtx_params* params, unsigned nbThread
     return nbThreads;
 }
 
+/* ZSTDMT_getNbThreads():
+ * @return nb threads currently active in mtctx.
+ * mtctx must be valid */
+size_t ZSTDMT_getNbThreads(const ZSTDMT_CCtx* mtctx)
+{
+    assert(mtctx != NULL);
+    return mtctx->params.nbThreads;
+}
+
 ZSTDMT_CCtx* ZSTDMT_createCCtx_advanced(unsigned nbThreads, ZSTD_customMem cMem)
 {
     ZSTDMT_CCtx* mtctx;
diff --git a/lib/compress/zstdmt_compress.h b/lib/compress/zstdmt_compress.h
index 4209cf3c..d12f0adb 100644
--- a/lib/compress/zstdmt_compress.h
+++ b/lib/compress/zstdmt_compress.h
@@ -114,9 +114,14 @@ size_t ZSTDMT_CCtxParam_setMTCtxParameter(ZSTD_CCtx_params* params, ZSTDMT_param
 
 /* ZSTDMT_CCtxParam_setNbThreads()
  * Set nbThreads, and clamp it correctly,
- * but also reset jobSize and overlapLog */
+ * also reset jobSize and overlapLog */
 size_t ZSTDMT_CCtxParam_setNbThreads(ZSTD_CCtx_params* params, unsigned nbThreads);
 
+/* ZSTDMT_getNbThreads():
+ * @return nb threads currently active in mtctx.
+ * mtctx must be valid */
+size_t ZSTDMT_getNbThreads(const ZSTDMT_CCtx* mtctx);
+
 /*! ZSTDMT_initCStream_internal() :
  *  Private use only. Init streaming operation.
  *  expects params to be valid.