diff --git a/prime_factors.rb b/prime_factors.rb
new file mode 100644
index 0000000..feb16a8
--- /dev/null
+++ b/prime_factors.rb
@@ -0,0 +1,10 @@
+require 'prime'
+class PrimeFactors
+  def self.for(num)
+    return [] if num == 1
+    result = []
+    num = num.prime_division
+    num.each { |i| i[1].times { result << i[0] } }
+    result
+  end
+end