Bovine brucellosis is an infectious zoonotic disease causing significant economical loses in dairy industry. A cross-sectional study was carried out between October 2017 and July 2018 to estimate the seroprevalence and its associated risk factors in smallholder dairy farms in Hawassa town, Southern Ethiopia. A total of 370 blood samples were collected from cross-bred and local indigenous dairy cattle of above six months of age. One stage cluster sampling technique was used to get the sample of interest. Rose Bengal Plate Test (RBPT) was used as a screening, while serum samples testing positive to RBPT were subjected for complement fixation test (CFT) to confirm. Consequently, RBPT detected 18 of the 370 samples positive for brucellosis exposure. The positive sera when further retested using CFT, 10 out of the 18 RBPT positive sera were confirmed to be positive. The individual animal level prevalence of bovine brucellosis in the study area was 2.7% and the herd-level prevalence was 25.8%. Higher prevalence was observed in larger herd sizes than the small and medium herds (p<0.05). Likewise, parity number greater than six had more positive animals (p<0.05) than the corresponding group with lower parity number. Multivariable logistic regression anlysis revealed that herd sizes (