Vienna Fortran 90 is a language extension of Fortran 90 which enables the user to write programs for distributed memory multiprocessors using global data references only. Performance of software on such systems is profoundly influenced by the manner in which data is distributed to the processors. Hence, Vienna Fortran 90 provides the user with a wide range of facilities for the mapping of data to processors. Thus it combines the advantages of the shared memory programming paradigm with mechanisms for explicit user control of those aspects of the program which have the greatest impact on efficiency. This paper presents the major features of Vienna Fortran 90 and gives examples of their use.