The correlator output binary data format defines files that are to be a part of the complete scientific data set associated with an EVLA observation. The format of the complete scientific data of an observation is defined by the so-called Science Data Model (or SDM) maintained jointly by the CASA group at NRAO, and the EVLA project. The CASA group will provide the image processing software for the EVLA, and, as such, will be designing and implementing one of the primary “consumers” of the correlator output binary data files. The specification of both the SDM and the binary data format given by this document are, therefore, jointly developed and maintained by both groups. A document for the EVLA project specifying the SDM, and providing important contextual information related to the present specification, will be produced in the near future. Joe McMullin should be listed as a co-author or co-editor of this document after he has had the opportunity to review it.