One of the characteristics of puberty is awareness of one's own sexuality. While searching in sexual behaviors sometimes put them awkward situations, yet this is how they exercise their sexuality. Deviations in sexual behavior such as paraphilia often begin in adolescence, transvestic fetishism is one of them. In this case report, 14-year-old male patient with mild mental retardation was brought with presenting symptoms of wearing his mother's undergarments. This cross-dressing behavior has been going on for about a year and usually ending with masturbation associated with feelings of relief and quilt. He seemed embarrassed and was defensive to related questions, avoiding eye contacts and his mood was depressive in his mental examination. Mild mental retardation was determinated in his intelligence test. Sertraline 50 mg/day was started for his depression and weekly based therapy with him and his family was outlined. The purpose of the therapy, to make him understand his deviated behavior as well as educate him as what to do appropriately with his sexual feelings. In this paper, relationship between transvestic fetishism and mental retardation, differential diagnosis of transvestic fetishism and psychodynamics of transvestic fetishism are discussed. Last of all, diagnose of transvestic fetishism at an early age and early intervention are important for a successful treatment. The importance of sexual education to youngsters besides dealing familial and psychosexual factors contribute to treatment process are discussed. The need and choice of pharmacological treatment are also discussed in the light of the literature.