diff --git a/build/cmake/CMakeLists.txt b/build/cmake/CMakeLists.txt
index fdf7c8637ea..5e2cf3d5634 100644
--- a/build/cmake/CMakeLists.txt
+++ b/build/cmake/CMakeLists.txt
@@ -82,7 +82,7 @@ message(STATUS "CMAKE_INSTALL_LIBDIR: ${CMAKE_INSTALL_LIBDIR}")
 #-----------------------------------------------------------------------------
 
 # Legacy support
-option(ZSTD_LEGACY_SUPPORT "LEGACY SUPPORT" OFF)
+option(ZSTD_LEGACY_SUPPORT "LEGACY SUPPORT" ON)
 
 if (ZSTD_LEGACY_SUPPORT)
     message(STATUS "ZSTD_LEGACY_SUPPORT defined!")
diff --git a/build/cmake/README.md b/build/cmake/README.md
index 73b30dc773b..f6854f4c05a 100644
--- a/build/cmake/README.md
+++ b/build/cmake/README.md
@@ -37,7 +37,7 @@ cmake -LH ..
 Bool options can be set to `ON/OFF` with `-D[option]=[ON/OFF]`. You can configure cmake options like this:
 ```sh
 cd build/cmake/builddir
-cmake -DZSTD_BUILD_TESTS=ON -DZSTD_LEGACY_SUPPORT=ON ..
+cmake -DZSTD_BUILD_TESTS=ON -DZSTD_LEGACY_SUPPORT=OFF ..
 make
 ```