Background: Antiretroviral therapy scales up globally and in Ethiopia, as a result, AIDS-related mortality has reduced, but the number of new HIV infections increasing. Antiretroviral therapy in Ethiopia gives a chance of living longer for reproductive-age women. Prevention of pregnancy among HIV positive women is the second WHO prongs of HIV transmission with respecting women's reproductive rights. Antiretroviral therapy uses improve the health of HIV positive women using and women's fertility desire increasing. Therefore this study aimed to assess the fertility desire and associated factors among ART user reproductive-age women.Methods: A facility-based cross-sectional study design conducted from November 2-30/2018. The calculated sample size was 400 and study participants were selected by using systematic random sampling. A pre-tested structured questionnaire was used to collect data. A binary logistic regression model was employed and adjusted odds ratio with a 95% confidence interval used to consider statistically significant Results: A total of 397 clients were participated in the study, giving a response rate of 99.3%. The proportion of fertility desire in this study was 55.2 %(95% CI, 50.4%-60.2%). A duration of marriage < 4 year [AOR=6.9(95 CI: 1.65, 28.81)], and 5-9 years duration of marriage [AOR= 13.8 (95% CI: 2.39, 80.39)] higher as compared to 15 years and above, family influence 3.4 times more likely to have fertility desire than have no family influence [AOR= 3.4 (95% CI: 1.06, 11.25)], partner desire 4.3 times more likely have had fertility desires as compared to with counterpart [AOR= 4.3 (95% CI:1.93,9.41)], and discussion with health care provider 66 % less likely to have fertility desire as compared with counterpart [AOR = 0.34 (95% CI: 0.39, 3.31)].Conclusion: In this study, we have identified a high proportion of fertility desire among ART user reproductive-age women. The duration of marital status, partner influence, family influence, and discussion of health care were associated with fertility desire. Family-oriented counseling, partner involvement on reproductive health services should be encouraged to support the rights of all women to safely achieve their fertility.