diff --git a/ChangeLog b/ChangeLog
index 56d408b..bba5e54 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,7 +7,7 @@
         Load CTA GTI extension from the HDU name provided by the DSS keyword (#1598)
 
 
-2016-01-13  Juergen Knoedlseder  <jurgen.knodlseder@irap.omp.eu>
+2016-01-22  Juergen Knoedlseder  <jurgen.knodlseder@irap.omp.eu>
 
         * Bug fix version 1.0.1 released
         ================================
@@ -15,6 +15,7 @@
         Add units to CTA event list columns (#1616)
         Allow usage of numbers in FITS extension names (#1611)
         Solve compatibility issues with Anaconda on Mac OS X (#1607)
+        Correct diffuse map MC normalisation (#1584)
 
 
 2015-12-18  Juergen Knoedlseder  <jurgen.knodlseder@irap.omp.eu>
diff --git a/src/model/GModelSpatialDiffuseMap.cpp b/src/model/GModelSpatialDiffuseMap.cpp
index 2c31ad3..0b385cb 100644
--- a/src/model/GModelSpatialDiffuseMap.cpp
+++ b/src/model/GModelSpatialDiffuseMap.cpp
@@ -719,11 +719,18 @@ void GModelSpatialDiffuseMap::set_mc_cone(const GSkyDir& centre,
         // Make sure that last pixel in the cache is >1
         m_mc_cache[npix] = 1.0001;
 
-        // Set the normalization factor for the MC simulations as the
-        // fraction of the flux that is comprised within the simulation
-        // cone
+        // Set the normalization factor for the MC simulations. In case
+        // that the map is normalized, this is the fraction of the flux
+        // that is comprised within the simulation cone. For non-normalized
+        // maps, this is simply the flux comprised within the simulation
+        // cone.
         if (sum_map > 0.0) {
-            m_mc_norm = sum / sum_map;
+            if (m_normalize) {
+                m_mc_norm = sum / sum_map;
+            }
+            else {
+                m_mc_norm = sum;
+            }
         }
 
         // Do we have a HealPix map?