diff --git a/pygal/svg.py b/pygal/svg.py
index aa1bbe3..d72c1e6 100644
--- a/pygal/svg.py
+++ b/pygal/svg.py
@@ -491,4 +491,8 @@ class Svg(object):
         for serie in self.graph.series:
             if serie.stroke_style is not None:
                 css.append(stroke_dict_to_css(serie.stroke_style, serie.index))
+
+        for secondary_serie in self.graph.secondary_series:
+            if secondary_serie.stroke_style is not None:
+                css.append(stroke_dict_to_css(secondary_serie.stroke_style, secondary_serie.index))
         return '\n'.join(css)