Introduction: Primary amenorrhoea is defined as absence of menstruation by the age of 14 in absence of secondary sexual characteristics & by age 16 regardless of the presence or absence of secondary sexual characteristics. It occurs in around 1-4% of women in reproductive age group. The common causes of primary amenorrhoea include outflow tract disorders or uterine abnormalities, ovarian disorders, pituitary dysfunction, and hypothalamic dysfunction.The data of primaryamenorrhoea from our country is limited due to poor reporting and frequent loss to follow up. Hence we undertook this prospective study to determine the etiology for primary amenorrhoeabased on clinical examination and laboratory investigations. Methodology: This prospective study was done in Gynecologic Clinic of Sunrise Hospital between August 2013 to May 2015. The work up of primary amenorrhoea patients comprised of 1) History taking 2) Physical examination 3) Laboratory investigations. Patients were classified into 5 groups based on the compartment of organs involved.I-End organ failure/ outflow tract obstruction, II-Gonadal failure, III-Pituitary cause, IV-Hypothalamic cause, V-Other causes. Results: In our study, the 2 most common etiologic factors of primary amenorrhoeawere mullerian agenesis (65.78%) and gonadal dysgenesis (21.05%).Hypogonadotrophichypogonadism was noted in 10.52% of cases. Range of average age of the patients when they first consulted the physician was 14 to 33 years. Conclusion: Prompt reporting and awareness of available treatment options based on the etiology can make a huge difference in this often underreported disorder.