diff --git a/ChangeLog b/ChangeLog
index 56a4ab2b6..fad00b7aa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -96,6 +96,7 @@
 - Regular expressions are now enabled by default.
 - New verbosity token 'filter' shows the complete filter used by the last
   command.
+- Display debug/release build type in the diagnostics command.
 
 ------ current release ---------------------------
 
diff --git a/cmake.h.in b/cmake.h.in
index 7bd25a6b5..315ee5465 100644
--- a/cmake.h.in
+++ b/cmake.h.in
@@ -12,6 +12,8 @@
 #define PACKAGE_VERSION   "${PACKAGE_VERSION}"
 #define PACKAGE_STRING    "${PACKAGE_STRING}"
 
+#define CMAKE_BUILD_TYPE  "${CMAKE_BUILD_TYPE}"
+
 /* Installation details */
 #define TASK_RCDIR "${CMAKE_INSTALL_PREFIX}/${TASK_RCDIR}"
 
diff --git a/src/commands/CmdDiagnostics.cpp b/src/commands/CmdDiagnostics.cpp
index fa48b97d8..d371cb50e 100644
--- a/src/commands/CmdDiagnostics.cpp
+++ b/src/commands/CmdDiagnostics.cpp
@@ -174,6 +174,14 @@ int CmdDiagnostics::execute (std::string& output)
 #endif
 #else
       << "n/a"
+#endif
+      << "\n";
+
+  out << " Build type: "
+#ifdef CMAKE_BUILD_TYPE
+      << CMAKE_BUILD_TYPE
+#else
+      << "-"
 #endif
       << "\n\n";