We report case of partial androgen insensitivity syndrome in a 12-year-old boy referred to our clinic complaining of bilateral gynecomastia and left undescended testicle. Laparoscopy for undescended testicle and bilateral mastectomy were performed, and the left testicle was absent. When skin fibroblasts of the scrotum obtained during surgery were cultured to analyse the androgen receptors, a slight thermolability was observed. Genomic examination of the androgen receptor gene could not detect any mutations.