Objective: To report a case of an azoospermic subject with mild androgen insensitivity syndrome (MAIS) and review the relevant literature. Design: Case report. Setting: Academic research hospital. Patient(s): A 49-year-old man with undermasculinized features and a history of cryptorchidism and azoospermia. Intervention(s): Hormonal evaluation and genetic testing of the androgen receptor gene (AR). Main Outcome Measure(s): Hormonal levels and sequence chromatogram of the proband and his mother. Result(s): We found total T in the normal range and high levels of gonadotropins. Karyotype was 46,XY. Genetic testing identified a novel mutation of exon 1 of AR, which resulted in an alanine to serine substitution in the transactivation domain at codon 240 (A240S). Fourteen other mutations of exon 1 of AR have been associated with MAIS to date. Conclusion(s): The novel mutation A240S of AR is involved in MAIS, a syndrome associated with azoospermia. [ABSTRACT FROM AUTHOR]