Abstract: Background: Contraceptive discontinuation by other factors than the desire for pregnancy is a public health concern because of its association with negative reproductive health outcomes. The coverage of contraceptive use is low in Tanzania and especially in Mwanza region and is known regarding the magnitude of contraceptive discontinuation and its associated factors within the region. This study was conducted to assess magnitude and factors contributing to contraceptive discontinuation among women of reproductive-age in Ilemela Municipality in Mwanza region. Methods: We conducted a community based quantitative cross sectional study in Ilemela Municipality in Mwanza region. A total of 353 women aged 18-49 years were recruited in the survey through systematic random sampling technique. Socio-demographic data and factors associated with discontinuation of contraceptive among women of reproductive age were collected using structured interviewer-administered questionnaire, and analysed by using STATA version 13. The main outcome was discontinuation of contraceptive among women of reproductive age. To determine independent factors associated with contraceptive discontinuation among women of reproductive-age, we employed Pearson Chi2 test and univariate followed by multivariate logistic regression analyses. Results: Of the 353 participants enrolled in the study, 191 (54.1%) discontinued contraceptive methods while they still needed to avoid pregnancy. The injectable contraceptive method had the highest discontinuation rate (64.4%). In a univariate logistic regression model, factors found to be associated with contraceptive discontinuation include, women who did not have to tendency to consult health workers (OR 1.7; 95% CI 1.1-2.9; p-value 0.045), women who experienced challenges in using contraceptive methods (OR 5.3; 95% CI [3.3-8.3]; p-value <0.001), women who sometimes by contraceptive methods (OR=1.6;95% CI [1.1-2.5]; p-value=0.043), women who sometimes missed contraceptives at the facility (OR=1.7; 95% CI [1.0-3.1]; p-value 0.056) and women whose their partners had a negative feeling on contraceptives (OR=2.1; 95 CI [1.3-3.3]; p-value 0.002). On multivariate logistic regression analysis, factors which showed a significant association with contraceptive discontinuation after adjusting for potential confounders were women who experienced challenges (OR 4.8; 95%CI 2.9-7.8; p-value>0.001) and women whose partner’s feeling was negative on contraceptives (OR 1.8; 95% CI 1.1-3.0; p-value 0.028). Conclusion: The prevalence of contraceptive discontinuation is very high in the district and is independently associated with a history of experienced challenges and negative partner’s feeling on contraceptives. A comprehensive counselling and health education on appropriate use of contraceptive methods and management of expected side effects and challenges during their use should be emphasized during family planning services. The Ministry of Health and reproductive health stakeholders should ensure that contraceptive methods are available all the time at the health facility clinics. Husbands and male partners need proper education and information on modern contraceptives, including their side effects, in order to enhance their positive support to women on utilizing contraceptives will increase their support to women on contraceptive utilization. Mixed methods should be encouraged in facilities and clients need to be advised to use other contraceptives options like IUCD and implants.