Mullerin agenesis also referred as mullerian aplasia, Mayer-Rokitansky-Kuster-Hauser Syndrome (MRKH) or vaginal agenesis is the congenital anomaly of vertical fusion defect of mullerian system resulting in variable abnormalities of female reproductive tract with normal functioning ovaries. It is second most common cause of primary amenorrhea after gonadal agenesis. The occurrence of mullerian agenesis in twins is very rare. We present the case of one of the non-identical twins, 22 years female, with primary amenorrhea. Her elder twin sister had a normal female reproductive system. In our case, diagnosis was supported by presence of definitive primary amenorrhea with well-developed secondary sexual characteristics. Normal physiological hormonal levels ruled out the ovarian or pituitary pathology. Imaging studies like ultrasonography and magnetic resonance imaging (MRI) provided additional confirmation.