An advanced transaction model for CSCW applications—FCFM (flexible cooperative transaction model) is presented in this paper. Firstly, the definition of cooperative transactions is given and the states of them are specified. Secondly, the dependencies among cooperative transactions and those between cooperative transactions and outside environments are specified in terms of states of cooperative transactions. Finally, the serializability correctness criterion for the presented model is specified by state dependencies of cooperative transactions.The main advantage of FCTM is that users can customize the states and state dependencies of cooperative transactions to reflect the different requirements of CSCW applications.