diff --git a/seaborn/distributions.py b/seaborn/distributions.py
index 9d96eef738..e7643e814d 100644
--- a/seaborn/distributions.py
+++ b/seaborn/distributions.py
@@ -366,7 +366,7 @@ def violinplot(vals, groupby=None, inner="box", color=None, positions=None,
         x = positions[i]
 
         # If we only have a single value, plot a horizontal line
-        if len(a) == 1:
+        if len(np.unique(a)) == 1:
             y = a[0]
             if vert:
                 ax.plot([x - widths / 2, x + widths / 2], [y, y], **inner_kws)
diff --git a/seaborn/tests/test_distributions.py b/seaborn/tests/test_distributions.py
index d7ffff42c5..c28f7f46c5 100644
--- a/seaborn/tests/test_distributions.py
+++ b/seaborn/tests/test_distributions.py
@@ -284,6 +284,12 @@ def test_multi_violins_single_obs(self):
         nt.assert_equal(len(ax.lines), 11)
         plt.close("all")
 
+        data = [np.random.randn(30), [0, 0, 0]]
+        ax = dist.violinplot(data)
+        nt.assert_equal(len(ax.collections), 1)
+        nt.assert_equal(len(ax.lines), 6)
+        plt.close("all")
+
     @classmethod
     def teardown_class(cls):
         """Ensure that all figures are closed on exit."""