Aromatase deficiency is a rare autosomal recessive genetic disorder with an unknown incidence. Aromatase converts androgens into estrogen in the gonadal and extra-gonadal tissues. Aromatase deficiency causes ambiguous genitalia in the Female fetus and maternal virilization (hirsutism, acne, cliteromegaly, deep voice) during pregnancy due to increased concentration of androgens. A 19 months old girl patient was assessed due to presence of ambiguous genitalia. There were findings of maternal virilization during pregnancy. The karyotype was 46,XX. Congenital adrenal hyperplasia was not considered since adrenocorticotropic hormone, cortisol, and 17-hydroxyprogesterone levels were within normal ranges. At age two months, follicle-stimulating hormone and total testosterone levels were elevated and estradiol level was low. Based on these findings, aromatase deficiency was suspected. A novel homozygous mutation IVS7-2A > G (c.744-2A >G) was identified in the CYP19A1 gene. Pelvic ultrasound showed hypoplasic ovaries rather than large and cystic ovaries. We identified a novel mutation in the CYP19A1 gene in a patient who presented with ambiguous genitalia and maternal virilization during pregnancy. Presence of large and cystic ovaries is not essential in aromatase deficiency.