diff --git a/mdbx.h b/mdbx.h
index 6a51768d..aa9c2653 100644
--- a/mdbx.h
+++ b/mdbx.h
@@ -328,6 +328,10 @@ typedef enum MDB_cursor_op {
  * right now (e.g. in readonly mode and so forth). */
 #define MDBX_WANNA_RECOVERY (-30419)
 
+/* The given key value is mismatched to the current cursor position,
+ * when mdbx_cursor_put() called with MDB_CURRENT option. */
+#define MDBX_EKEYMISMATCH (-30418)
+
 /* Statistics for a database in the environment */
 typedef struct MDBX_stat {
   unsigned ms_psize;        /* Size of a database page.
diff --git a/src/mdbx.c b/src/mdbx.c
index 699d0bff..997bf987 100644
--- a/src/mdbx.c
+++ b/src/mdbx.c
@@ -759,6 +759,9 @@ static const char *__mdbx_strerr(int errnum) {
   case MDBX_WANNA_RECOVERY:
     return "MDBX_WANNA_RECOVERY: Database should be recovered, but this could "
            "be done in a read-only mode";
+  case MDBX_EKEYMISMATCH:
+    return "MDBX_EKEYMISMATCH: The given key value is mismatched to the "
+           "current cursor position";
   default:
     return NULL;
   }
@@ -5729,7 +5732,7 @@ int mdbx_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
           mc->mc_ki[mc->mc_top]++;
         } else {
           /* new key is <= last key */
-          rc = MDB_KEYEXIST;
+          rc = MDBX_EKEYMISMATCH;
         }
       }
     } else {