In the context of prospective trials of immunosuppressive drugs in systemic lupus erythematosus (SLE) nephritis, 83 patients were studied with regard to development of herpes zoster. Herpes zoster was found to occur with high frequency (21%) in patients with SLE nephritis treated with immunosuppressive agents. The course of herpes zoster was benign: no deaths occurred and only 2 of the 18 patients developed generalized disease, which resolved without sequelae. Specific antiviral therapy was not necessary and there appears to be no need to decrease immunosuppressive medications. Zoster occurred when the SLE was relatively inactive and did not exacerbate the SLE. No statistical difference in the incidence of zoster was found among the patient groups treated with different immunosuppressive regimens.