A simple way to offer a Grid access through a middleware is to use the GridRPC paradigm. It is based on the classical RPC model and extended to Grid environments. Client can access to remote servers as simply as a function call. Several middlewares are compliant to this paradigm as DIET, GridSolve, or Ninf-G. Actors of these projects have worked together to design a standard API within the Open Grid Forum. In this chapter we give an overview of this standard and the current works around the data management. Three use cases are introduced through a detailled descriptions of DIET, GridSolve, and Ninf-G middleware features. Finally applications for each middleware are shown to appreciate how they take benefit of the GridRPC API.