diff --git a/configure.ac b/configure.ac
index 891e73b..fdb1eed 100644
--- a/configure.ac
+++ b/configure.ac
@@ -36,6 +36,7 @@
 # Checks for typedefs, structures, and compiler characteristics.
 AX_CXX_COMPILE_STDCXX_17([noext])
 AX_APPEND_COMPILE_FLAGS([-fpic -Wall -Werror], [CFLAGS CXXFLAGS])
+AX_BOOST_BASE([1.66],, [AC_MSG_ERROR(["Requires boost."])])
 
 # Checks for library functions.
 LT_INIT([disable-static shared])