diff --git a/optional_requirements.txt b/optional_requirements.txt
index ea820151245ce3baa891132d4463cc5ff0d3db16..3e244261c52caa23509b0a05653db87c968bcbaa 100644
--- a/optional_requirements.txt
+++ b/optional_requirements.txt
@@ -2,4 +2,3 @@ astropy
 lalsuite<=6.48.1.dev20180823
 gwpy
 theano
-cpnest
\ No newline at end of file
diff --git a/test/sampler_tests.py b/test/sampler_tests.py
index cd59e651a6f4c2c0b34de48352d876f707907ebb..39e032a6065c3df753ecd3cf50c8b1eb478d8032 100644
--- a/test/sampler_tests.py
+++ b/test/sampler_tests.py
@@ -127,25 +127,5 @@ class TestSampler(unittest.TestCase):
         self.assertDictEqual(sampler_copy.__dict__, self.sampler.__dict__)
 
 
-class TestCPNest(unittest.TestCase):
-
-    def setUp(self):
-        def func(x, mu, sigma): return (mu-x) ** 2 / (2 * sigma**2)
-        self.likelihood = tupak.core.likelihood.GaussianLikelihood(
-            np.random.uniform(0, 1, 100), np.random.uniform(0, 1, 100),
-            func)
-
-    def tearDown(self):
-        del self.likelihood
-
-    def test_cannot_run_with_gaussian_prior(self):
-        priors = dict(mu=tupak.prior.Gaussian(0, 1),
-                      sigma=tupak.prior.Uniform(0, 1))
-        sampler = tupak.core.sampler.Cpnest(
-            likelihood=self.likelihood, priors=priors,
-            external_sampler='cpnest')
-        self.assertRaises(ValueError, lambda: sampler._run_external_sampler())
-
-
 if __name__ == '__main__':
     unittest.main()