diff --git a/var/spack/repos/builtin/packages/mercury/package.py b/var/spack/repos/builtin/packages/mercury/package.py
index fe881119ed..ab56c6395e 100644
--- a/var/spack/repos/builtin/packages/mercury/package.py
+++ b/var/spack/repos/builtin/packages/mercury/package.py
@@ -39,6 +39,8 @@ class Mercury(CMakePackage):
             description='Enable udreg on supported Cray platforms')
     variant('debug', default=False,
             description='Enable Mercury to print debug output')
+    variant('checksum', default=True,
+            description='Checksum verify all request/response messages')
 
     depends_on('cmake@2.8.12.2:', type='build')
     # depends_on('cci', when='+cci')  # TODO: add CCI package
@@ -67,7 +69,7 @@ def cmake_args(self):
             '-DBUILD_TESTING:BOOL=%s' % str(self.run_tests),
             '-DMERCURY_ENABLE_PARALLEL_TESTING:BOOL=%s' % str(parallel_tests),
             '-DMERCURY_USE_BOOST_PP:BOOL=ON',
-            '-DMERCURY_USE_CHECKSUMS:BOOL=ON',
+            '-DMERCURY_USE_CHECKSUMS:BOOL=%s' % variant_bool('+checksum'),
             '-DMERCURY_USE_SYSTEM_MCHECKSUM:BOOL=OFF',
             '-DMERCURY_USE_XDR:BOOL=OFF',
             '-DNA_USE_BMI:BOOL=%s' % variant_bool('+bmi'),