diff --git a/lib/cmath.gemspec b/lib/cmath.gemspec
new file mode 100644
index 0000000000..0287f730b2
--- /dev/null
+++ b/lib/cmath.gemspec
@@ -0,0 +1,16 @@
+Gem::Specification.new do |s|
+  s.name = "cmath"
+  s.version = '0.0.1'
+  s.date = '2017-02-02'
+  s.summary = "Provides Trigonometric and Transcendental functions for complex numbers"
+  s.description = "CMath is a library that provides trigonometric and transcendental functions for complex numbers. The functions in this module accept integers, floating-point numbers or complex numbers as arguments."
+
+  s.require_path = %w{lib}
+  s.files = %w{cmath.rb}
+  s.required_ruby_version = ">= 2.5.0"
+
+  s.authors = ["Tadayoshi Funaba"]
+  s.email = [nil]
+  s.homepage = "https://www.ruby-lang.org"
+  s.license = "BSD-2-Clause"
+end