Introduction: Androgen insensitivity syndrome (AIS), an X-linked recessive disorder of sex development (DSD), is caused by variants of the androgen receptor (AR) gene, mapping in the long arm of the X chromosome, which cause a complete loss of function of the receptor. Case presentation: We report a patient diagnosed with complete AIS (CAIS) at birth due to swelling in the bilateral inguinal region. Transabdominal ultrasound revealed the absence of the uterus and ovaries and the presence of bilateral testes in the inguinal region. The karyotype was 46,XY. She underwent bilateral orchiectomy at 9 months and was given estrogen substitutive therapy at the age of 11 years. Genetic analysis of the AR gene variants was requested when, at the age of 20, the patient came to our observation. Methods: The genetic testing was performed by next-generation sequence (NGS) analysis. Results: The genetic analysis showed the presence of the c.2242T>A, p.(Phe748Ile) variant in the AR gene. To the best of our knowledge, this variant has not been published so far. Furthermore, the patient has a heterozygous c.317A>G, p.(Gln106Arg) variation of the gonadotropin-releasing hormone receptor (GNRHR) gene, a heterozygous c.2273G>A, p.Arg758His variation of the chromodomain helicase DNA binding protein 7 (CHD7) gene, and compound heterozygous c.875A>G, p.Tyr292Cys, and c.8023A>G, p.Ile2675Val variations of the Dynein Axonemal Heavy Chain 11 (DNAH11) gene. Conclusions: The case herein reported underlines the importance of an accurate genetic analysis that has to include karyotype and AR gene variant analysis. This is useful to confirm a clinical diagnosis and establish the proper management of patients with CAIS. Numerous variants of the AR gene have not yet been identified. Moreover, several pitfalls are still present in the management of these patients. More studies are needed to answer unresolved questions, and common protocols are required for the clinical follow-up of patients with CAIS.