Biodegradability test for various synthetic lubricant oil bases derived from biodiesel was carried out. The biodegradability was estimated under aerobic aqueous condition, according to the method by OECD 301 B, which is based on CO$_2$ evolution test. The ultimate biodegradability of pentaerythritol methyl esters were estimated as 61.1∼80.3%, at 28 day with which the test compounds were indicated as ultimately biodegradable. Among the tested samples, biodiesel showed the highest biodegradability (83.5%). The validation with several criteria, regarding relative errors of test results, toxicity control and procedure control, was performed through the biodegradability test. The test procedure was validated for all the tested lubricant oil bases and biodiesel, except for petroleum diesel.