diff --git a/pymc3/distributions/continuous.py b/pymc3/distributions/continuous.py
index 80a943c83f4..2899e262003 100644
--- a/pymc3/distributions/continuous.py
+++ b/pymc3/distributions/continuous.py
@@ -18,6 +18,7 @@
 nodes in PyMC.
 """
 import numpy as np
+import theano
 import theano.tensor as tt
 from scipy import stats
 from scipy.special import expit
@@ -3341,7 +3342,7 @@ def logp(self, value):
 
         standardized_val = (value - mu) / sigma
         cdf_val = std_cdf(standardized_val - sigma / nu)
-        cdf_val_safe = tt.switch(tt.eq(cdf_val, 0), np.finfo(float).eps, cdf_val)
+        cdf_val_safe = tt.switch(tt.eq(cdf_val, 0), np.finfo(theano.config.floatX).eps, cdf_val)
 
         # This condition is suggested by exGAUS.R from gamlss
         lp = tt.switch(