diff --git a/CMakeLists.txt b/CMakeLists.txt
index 21fb43623f0..38ad7ab671e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,12 @@
 cmake_minimum_required(VERSION 3.2)
 
+# Build a Release version by default (default build flags for each build type
+# are configured below).
+if (NOT EXISTS ${CMAKE_BINARY_DIR}/CMakeCache.txt)
+    if (NOT CMAKE_BUILD_TYPE)
+        set(CMAKE_BUILD_TYPE "Release" CACHE STRING "" FORCE)
+    endif()
+endif()
 
 # Grab the current CBMC version from config.inc
 # We do this so we have a matching cbmc version between the Makefile build and
diff --git a/COMPILING.md b/COMPILING.md
index e4e5dece720..57a3b78eda5 100644
--- a/COMPILING.md
+++ b/COMPILING.md
@@ -266,7 +266,8 @@ require manual modification of build files.
    Generally it is not necessary to manually specify individual compiler or
    linker flags, as CMake defines a number of "build modes" including Debug and
    Release modes. To build in a particular mode, add the flag
-   `-DCMAKE_BUILD_TYPE=Debug` (or `Release`) to the initial invocation.
+   `-DCMAKE_BUILD_TYPE=Debug` (or `RelWithDebInfo`) to the initial invocation.
+   The default is to perform an optimized build via the `Release` configuration.
 
    If you *do* need to manually add flags, use `-DCMAKE_CXX_FLAGS=...` and
    `-DCMAKE_EXE_LINKER_FLAGS=...`. This is useful for enabling clang's