Imipramine is a tricyclic medication that has been used for the treatment of depression and other mood disorders. Although rare, a slate gray discoloration of sun-exposed skin may occur in patients taking this medication. We present the case of a 63-year-old woman who had been taking imipramine for depression for more than 20 years when she developed a bluish gray discoloration on the face and neck that was diagnosed as imipramine-induced hyperpigmentation based on histopathology and clinical history. A number of other drugs that may cause hyperpigmentation also are reviewed as well as their histopathologic staining characteristics.