Issue #3085 has been updated by Aaron Patterson. Priority changed from Normal to Low hmmm. Is this necessary? You can dump your time object as a rational if you need that kind of accuracy: $ irb irb(main):001:0> require 'psych' => true irb(main):002:0> time = Time.at(Time.now.sec, Rational(1, 3)) => 1969-12-31 16:00:28 -0800 irb(main):003:0> yaml = Psych.dump(time.to_r) => "--- !ruby/object:Rational\ndenominator: 3000000\nnumerator: 84000001\n" irb(main):004:0> time == Time.at(Psych.load(yaml)) => true irb(main):005:0> ---------------------------------------- http://redmine.ruby-lang.org/issues/show/3085 ---------------------------------------- http://redmine.ruby-lang.org