Background: Porphyria cutanea tarda is known to be associated with HIV infection and hepatitis C virus (HCV). Objective: Our purpose was to evaluate whether early infection with HIV, with or without HCV infection, is associated with elevated serum porphyrin levels. Methods: Serum porphyrin levels were measured in samples obtained from 103 patients with early HIV infection. The results were compared with those of 89 late-stage HIV–positive patients and 78 HIV-negative patients. Results: The highest median porphyrin level was in early-stage HIV-positive/HCV-positive samples, followed in decreasing order by those in early-stage HIV-positive/HCV-negative, late-stage HIV-positive/HCV-positive, late-stage HIV-positive/HCV-negative, HIV-negative/HCV-positive, and HIV-negative/HCV-negative groups. Elevated porphyrin levels were independently associated with early-stage HIV infection (P < .0001) and HCV infection (P = .03). Conclusion: This finding suggests abnormal porphyrin metabolism is most noticeable in early-stage HIV infection; it becomes less severe with the progression of HIV disease. (J Am Acad Dermatol 1998;39:956-9.)