diff --git a/spreadsheet.gemspec b/spreadsheet.gemspec
index 3ef5129..88cfc12 100755
--- a/spreadsheet.gemspec
+++ b/spreadsheet.gemspec
@@ -14,6 +14,7 @@ Gem::Specification.new do |spec|
    spec.test_file   = "test/suite.rb"
    spec.executables << "xlsopcodes"
 
+   spec.add_dependency "bigdecimal"
    spec.add_dependency "ruby-ole"
    spec.add_development_dependency "rake"
    spec.add_development_dependency "test-unit"