This study demonstrates that pregraphitic materials (cokes) of different origin (petroleum and coal derivatives) can be used as precursors of graphene oxides. Two carbochemical cokes and a petrochemical one were oxidized and the resultant coke oxides exfoliated by ultrasounds to yield the corresponding graphene oxide materials. These were characterized in terms of the lateral size of the sheets, morphology and chemical composition. The new generation of graphene oxides prepared with coke exhibits similar characteristics to those traditionally obtained from graphite. It is also established that as larger the crystalline structure of the coke is, the higher the graphene oxide yields and the larger the size of the sheets. (C) 2015 Elsevier Ltd. All rights reserved.