diff --git a/docs/sphinx/source/whatsnew/v0.6.1.rst b/docs/sphinx/source/whatsnew/v0.6.1.rst
index e53c374d3a..55e7e79986 100644
--- a/docs/sphinx/source/whatsnew/v0.6.1.rst
+++ b/docs/sphinx/source/whatsnew/v0.6.1.rst
@@ -50,6 +50,7 @@ Bug fixes
   and < 1900, fix year 2050 which was returning 0.
 * Fix and improve :func:`~pvlib.solarposition.hour_angle` (:issue:`598`)
 * Fix error in :func:`pvlib.clearsky.detect_clearsky` (:issue:`506`)
+* Fix error in :func:`pvlib.modelchain.ModelChain.infer_spectral_model` (:issue:`619`)
 
 
 Testing
diff --git a/pvlib/modelchain.py b/pvlib/modelchain.py
index b1e5f07b82..b1cd6ecfa7 100644
--- a/pvlib/modelchain.py
+++ b/pvlib/modelchain.py
@@ -622,7 +622,7 @@ def infer_spectral_model(self):
             return self.sapm_spectral_loss
         elif ((('Technology' in params or
                 'Material' in params) and
-               (pvsystem._infer_cell_type() is not None)) or
+               (self.system._infer_cell_type() is not None)) or
               'first_solar_spectral_coefficients' in params):
             return self.first_solar_spectral_loss
         else: