diff --git a/lib/hermod/xml_section_builder.rb b/lib/hermod/xml_section_builder.rb
index 02fc0da..5b3e7a9 100755
--- a/lib/hermod/xml_section_builder.rb
+++ b/lib/hermod/xml_section_builder.rb
@@ -152,6 +152,7 @@ def monetary_node(name, options={})
       end
 
       create_method(name, [], validators, options) do |value, attributes|
+        value = value.to_i
         if options[:optional] && value == 0
           [nil, attributes]
         else
diff --git a/spec/hermod/xml_section_builder/monetary_node_spec.rb b/spec/hermod/xml_section_builder/monetary_node_spec.rb
index e40b1fe..6bfdf54 100644
--- a/spec/hermod/xml_section_builder/monetary_node_spec.rb
+++ b/spec/hermod/xml_section_builder/monetary_node_spec.rb
@@ -51,6 +51,14 @@ module Hermod
         ex = proc { subject.student_loan 0 }.must_raise Hermod::InvalidInputError
         ex.message.must_equal "student_loan cannot be zero"
       end
+
+      it "should treat blank nodes as zero nodes" do
+        subject.ni nil
+        value_of_node("NI").must_equal "0.00"
+
+        subject.tax nil
+        nodes("Tax").must_be_empty
+      end
     end
   end
 end