The synthesis of graphene oxide is discussed in this critical review. Particular emphasis is directed towards the conventional methods for the synthesis of graphene oxide (GO), their draw backs and modifications to enhance the efficiency of conventional synthetic routes. Moreover, this review covers the comparison of all the existing techniques for the graphene oxide synthesis. This review will be of value to the researchers interested in this emerging field of material science for developing the synthetic recipe in order to attain specific morphologies of GO for particular applications. (C) 2016 Elsevier B.V. All rights reserved.