The use of reporter constructs of HIV-1 molecular clones has been useful in studying the effects of infection on individual cells. A strategy of producing viral half-genome constructs containing reporter genes that can be used to produce recombinant complete infectious virions is described. This approach allows rapid generation of reporter and non-reporter virions from the same genetic construct, obviating the need to produce a new reporter genetic construct for each viral change to be studied. We provide an example of the utility of this system for studying the effects of Nef on infected cells.