Complete androgen insensitivity syndrome (CAIS) is a sexual differentiation disorder, caused by a defect in the androgen receptor gene (AR; OMIM# 313700). It is characterized by the resistance of target tissues to the action of testosterone, which prevents normal male genital development. The objective is to describe a family case of CAIS and highlight the importance of multidisciplinary medical management and early diagnosis of this syndrome.We present two cases of SICA in a Mexican family. Case 1: 18-year-old female patient with primary amenorrhea and a history of surgery at an early age, without performing gonadectomy. Case 2: 11-year-old female patient who, due to the history of her sister, underwent surgery at that age. In both patients, absence of uterus and ovaries, hypoplastic vagina and male gonads is reported. The 46,XY karyotype was detected with the GTG and CBG band technique and fluorescent in situ hybridization with the presence of the Y chromosome in 100% of the cells analyzed. Although both patients were identified with their assigned sex, they were referred to the institution's psychiatric clinic.The importance of multidisciplinary management for the diagnosis of SICA at an early age is discussed, in order to make decisions regarding the treatment and management of patients, avoiding malignant transformation of the male gonads.© 2023 Revista Médica del Instituto Mexicano del Seguro Social.