Introduction: Because of ART access and its good life effect, it is expected that PLHIV's need, and purpose would change with regard to reproductive health like to get married, desire to have children, and to have sexual partners among others. In Ethiopia, HIV-positive individuals may or may not have the desire to have children. But the level of these desires and how it varies by individual, social, health, and demographic characteristics is not well understood. In the study area, there has been little research on fertility desire among PLHIV and related variables Objectives: To assess fertility desire and associated factors among ART users at public hospitals of Sidama National Regional State, Ethiopia, 2023. Method and materials: An Institutional based cross-sectional study was conducted on randomly selected 403 ART users from February, 1-30, 2023. Data were gathered by using structured intervieweradministered questions and skilled data collectors. EpiData V4.4.1 was used to enter the data, and SPSS Version 25 was used for analysis. Bivariable and Multivariable logistic regressions were used. The association was reported using the adjusted odds ratio (AOR) with a 95% confidence interval (CI), and the significance level was set at a p-value of 0.05 Result: The prevalence of fertility desire among antiretroviral therapy users in the study area was 40.2% (95% CI 36.5-45.5%). Age 18–29 years [AOR = 7.9.3, 95% CI (2.55, 24.51)], had no formal education [AOR= 3.4, 95% CI (1.26, 9.27)], had no live children [AOR=3.8, 95% CI (1.32, 10.87], not use family planning [AOR = 3.5, 95% CI (1.57, 7.71)] and good knowledge on prevention of mother to child transmission of HIV [AOR = 2.9, 95% CI(1.17,7.53] had a positive association with fertility desire. Conclusion and recommendations: The prevalence of fertility desire in this study was high as compared to the national target. Emphasis to educate ART users, protecting rights and decisions of fertility desire of people living with HIV and enhancing a range of family planning method options access from all HIV/AIDS care units and focusing on prevention of mother-to-child transmission of HIV should be encouraged.