A young eunuchoid man was referred to our hospital with suspected erythropoietic protoporphyria. Serum antinuclear antibody (ANA) was found to be positive immediately after the porphyria attack and disappeared 30 days later. Many authors have mentioned the coexistence of systemic lupus erythematosus (SLE) and porphyria. As these two disorders have similar clinical features, the clinician must be alert and use strict diagnostic criteria in determining the presence of SLE with porphyria. In the past, elevation of ANA was reported in the cases of acute intermittent porphyria. However, there have been no reports in the cases of erythropoietic protoporphyria. In addition, the patient was found to have hypogonadotropic hypogonadism consistent with Kallmann's syndrome. To our knowledge, this report is the first case showing the coexistence of Kallmann's syndrome and erythropoietic protoporphyria. As yet, the clinical importance of this association remains unknown.