diff --git a/2560.py b/2560.py
new file mode 100644
index 0000000000..2f085baf0d
--- /dev/null
+++ b/2560.py
@@ -0,0 +1,15 @@
+import pymc3 as pm
+with pm.Model() as model:
+    a = pm.Gamma('a', mu=10.0, sd=2.0)
+    b = pm.Gamma('b', mu=10.0, sd=2.0)
+
+    trace = pm.sample(trace=[model.a, model.a_log__])
+    assert len(trace.varnames) == 2
+# you have to provide 4 vars:    
+#    trace = pm.sample(trace=[model.a, model.a_log__, model.b, model.b_log__])
+
+    pm.backends.text.dump('trace.text', trace)
+
+    loaded = pm.backends.text.load('trace.text')
+    print("loaded: ", loaded)
+    x = loaded[0] #!!! Will throw a KeyError looking for 'b_log__'
diff --git a/pymc3/backends/text.py b/pymc3/backends/text.py
index d5bec95639..3b84a72017 100644
--- a/pymc3/backends/text.py
+++ b/pymc3/backends/text.py
@@ -19,6 +19,7 @@
 import os
 import pandas as pd
 
+from ..model import modelcontext
 from ..backends import base, ndarray
 from . import tracetab as ttab
 from ..theanof import floatX
@@ -184,7 +185,7 @@ def load(name, model=None):
     return base.MultiTrace(straces)
 
 
-def dump(name, trace, chains=None):
+def dump(name, trace, model=None, chains=None):
     """Store values from NDArray trace as CSV files.
 
     Parameters
@@ -200,6 +201,12 @@ def dump(name, trace, chains=None):
         os.mkdir(name)
     if chains is None:
         chains = trace.chains
+    model = modelcontext(model)
+    model_vars = sorted([x.name for x in model.unobserved_RVs])
+    trace_vars = sorted(trace.varnames)
+
+    if model_vars != trace_vars:
+        raise ValueError('Variables mismatch: model_vars=' + str(model_vars) + ", trace_vars=" + str(trace_vars))
 
     for chain in chains:
         filename = os.path.join(name, 'chain-{}.csv'.format(chain))