diff --git a/pyqtgraph/exporters/HDF5Exporter.py b/pyqtgraph/exporters/HDF5Exporter.py
index cc8b5733..584a9f71 100644
--- a/pyqtgraph/exporters/HDF5Exporter.py
+++ b/pyqtgraph/exporters/HDF5Exporter.py
@@ -42,14 +42,20 @@ class HDF5Exporter(Exporter):
         dsname = self.params['Name']
         fd = h5py.File(fileName, 'a') # forces append to file... 'w' doesn't seem to "delete/overwrite"
         data = []
-        
+
         appendAllX = self.params['columnMode'] == '(x,y) per plot'
-        for i,c in enumerate(self.item.curves):
+        #print dir(self.item.curves[0])
+        tlen = 0
+        for i, c in enumerate(self.item.curves):
             d = c.getData()
+            if i > 0 and len(d[0]) != tlen:
+                raise ValueError ("HDF5 Export requires all curves in plot to have same length")
             if appendAllX or i == 0:
                 data.append(d[0])
+                tlen = len(d[0])
             data.append(d[1])
-                
+
+
         fdata = numpy.array(data).astype('double')
         dset = fd.create_dataset(dsname, data=fdata)
         fd.close()