Eight patients received cyclosporine at doses of 2.0 to 7.5 mg/kg/day. Seven of these patients had increased fasting plasma triglyceride levels with cyclosporine therapy compared with pretreatment values, which peaked after 1 month of therapy. Four patients experienced elevations in fasting triglycerides, over the upper limits for age- and sex-matched controls, which were at least two times higher than their baseline values. It was striking that all four of these patients had previously had hypertriglyceridemia while using etretinate and three of these patients had preexisting hypertriglyceridemia before both etretinate and cyclosporine therapy. Triglyceride elevation did not correlate with cyclosporine levels. Thus cyclosporine, similar to etretinate, unmasks a latent tendency for mild to moderate hypertriglyceridemia. Fasting triglyceride levels should be monitored during cyclosporine therapy, especially after 1 to 2 months of use, and in patients with preexisting increased triglycerides and/or a history of etretinate use.