diff --git a/pymbolic/mapper/__init__.py b/pymbolic/mapper/__init__.py
index 1ef44fe28d618a7bc8280936c4f602b6bda707c9..bac3b58c88b6cf894ee23765a4b35d15e4bfd5c9 100644
--- a/pymbolic/mapper/__init__.py
+++ b/pymbolic/mapper/__init__.py
@@ -993,6 +993,11 @@ class CachingMapperMixin:
         super().__init__()
         self.result_cache = {}
 
+        from warnings import warn
+        warn("CachingMapperMixin is deprecated and will be removed "
+                "in version 2023.x. Use CachedMapper instead.",
+                DeprecationWarning, stacklevel=2)
+
     def rec(self, expr):
         try:
             return self.result_cache[expr]