Introduction: The effects of early marriage among girls are devastating. While targeting to prevent such marriages, it is mandatory to know the current magnitude of the problem. For the State of Manipur, the figures available are quite contradictory to each other. Objective: A study was taken up to estimate the prevalence of women married before the age of 18 years in a Muslim-dominated area and also to study its association with key background characteristics. Material & methods: A cross-sectional study was done in Aug-Sept 2014 among ever-married women selected randomly from seven randomly selected villages out of all the existing 13 villages in Khetrigao area of Imphal East District, Manipur. Information about awareness of legal age of marriage, age at marriage and other background characteristics were collected by using a pre-tested semi-structured interview schedule. Results: Completed data sets were collected from 508 (96% of the calculated sample size of 530) study subjects. Only half of the study subjects knew the legal age female marriage. The awareness was statistically found to be higher among higher educated women. 184 study subjects out of all the study subjects got married before attaining the legal age giving a prevalence rate of 36%. The proportion of female early marriages showed a statistically significant decline among women married recently in the last five years compared to women married earlier. Key factors associated with female early marriage were low family income, parents being illiterate and low educational status of women and men. Type of family, family size, problems in family and type of guardianship were not associated with female early marriages. Discussion: The current study finding of 36% prevalence of female early marriage was higher compared to studies done under the aegis of Ministry of Health and Family Welfare, Govt. of India and also to studies done earlier. Key factors being low family income, lack of further education among females and illiterate parents were in accordance in other study findings done earlier and at different places. Conclusion: Concerted effort from various stake-holders to overcome the key factors associated with female early marriage is needed.