Trisomy X syndrome is a sex chromosome aneuploidy with a variable clinical presentation at different stages of life. We present two asyndromic females with primary infertility and features of premature ovarian failure (POF). The first case was a nonmosaic trisomy X with poor ovarian reserve on pelvic ultrasound and elevated gonadotropins, while the second case was a mosaic trisomy X who had partly preserved ovarian reserve with normal gonadotropins. The 47,XXX syndrome is a relatively uncommon presentation of POF, leading to infertility and can be missed clinically because of its variable presentation. Therefore, we suggest that genetic testing should be a part of early workup in young women presenting with primary infertility and POF for detecting chromosomal aneuploidies, which will require genetic counseling and alter the management.