Early cellular events after HIV-1 infection were accessed in material from T-cells (H9) and monocytes (U937) collected at various times during a single cycle of viral replication. Spliced RNA for HIV regulatory genes appeared 2-3 hr after HIV infection, while RNA for structural genes appeared at 3 hr. Formation and release of virion was delayed, since reverse transcriptase activity was first detected at 24 hr in cell lysates and between 1-5 days in culture medium. Results are in press in Oncogene.