diff --git a/pymc3/sampling.py b/pymc3/sampling.py
index 6c80b49472..85d8e95c93 100644
--- a/pymc3/sampling.py
+++ b/pymc3/sampling.py
@@ -142,6 +142,9 @@ def sample(draws, step=None, init='advi', n_init=200000, start=None,
     MultiTrace object with access to sampling values
     """
     model = modelcontext(model)
+    
+    if init is not None:
+        init = init.lower()
 
     if step is None and init is not None and pm.model.all_continuous(model.vars):
         # By default, use NUTS sampler