A 21-year-old phenotypic male with ambiguous external genitalia and hypospadias was referred for cytogenetic studies. Exploratory laparotomy revealed presence of a small atropic uterus, unilateral gonadal dysgenesis with fallopian tubes on both sides and a cryptorchid testis on the left side. No gonad could be traced on the right side. Chromosomal analysis from peripheral whole blood culture revealed a 46,XY cell line. No mosaicism was detected. Endocrine studies showed elevated levels of serum FSH and LH with low borderline testosterone level and failure to respond to HCG stimulation. The presence of fallopian tube next to testis suggests absence of anti-Mullerian hormone secretion by Sertoli cells. The absence of Wolffian duct derivatives indicates insufficient secretion of testosterone by Leydig cells.