OBJECTIVE: To report two cases of fixed drug eruption induced by methylphenidate. CASE SUMMARY: Two children with attention deficit disorder treated with methylphenidate as a simple drug developed fixed drug eruption of the scrotum. Drug discontinuation was followed by a complete resolution of the skin eruption. Rechallenge resulted in the same drug rash. Macrophage migration-inhibiting factor (MIF) assay with methylphenidate was positive. DISCUSSION: The pathogenesis of fixed drug eruption and the role of MIF assay in the diagnosis of adverse drug reaction is discussed. CONCLUSIONS: Fixed drug rash induced by methylphenidate is a possible but rare phenomenon.