Fossil fuel depletion, environmental concerns, and steep hikes in the price of fossil fuels are driving scientists to search for alternative fuels. The characteristics of biodiesel have made the pursuit of high quality biodiesel production attractive. Utilization of waste cooking oil is a key component in reducing biodiesel production costs up to 60-90%. Researchers have used various types of homogeneous and heterogeneous catalyzed transesterification reaction for biodiesel production. Meanwhile, the effect of novel processes such as membrane reactor, reactive distillation column, reactive absorption, ultrasonic and microwave irradiation significantly influenced the final conversion, yield and in particular, the quality of product. This article attempts to cover all possible techniques in production of biodiesel from waste cooking oil. (C) 2012 Elsevier Ltd. All rights reserved.