A quantitative cross-sectional and retrospective study design was carried out between November 2022 to April 2023 on small ruminant and human brucellosis, respectively. This study was conducted in Bahir Dar Zuria and North Mecha Districts, and at Bahir Dar University’s Tibebe Ghion Specialized Hospital, West Gojjam Zone, North West Ethiopia. The objectives of the study were to; i) estimate the prevalence of small ruminant Brucellosis, ii) estimate the prevalence of brucellosis in humans, iii) identify the associated putative risk factors affecting the sero-prevalence of brucellosis both in small ruminants and humans. A multistage stratified sampling technique was used to sample study Districts and the respective small ruminant producers and animals. Whereas purposive sampling was used to obtain human serum samples at Tibebe Ghion Specialized Hospital. A pre-tested structured interview questionnaire was used to collect data from small ruminant producers and hospitalized human respondents. A total of 384 small ruminant and 384 human samples were taken and analyzed for this study. All serum samples were first screened using Rose Bengal Plate test (RBPT) and finally confirmed by Complement Fixation test (CFT). Among the 384 small ruminant serum samples tested by RBPT and CFT, only 12 (3.13%) and 0 (0%) samples were found positive, respectively. Similarly, out of 384 human serum samples tested by RBPT and CFT; only 16 (4.16%) and 2 (0.52%) were found positive, respectively. The putative risk factors which were assumed to have associations with small ruminant and human brucellosis was not examined due to insufficient Brucella positive samples. However, the prevalence of human brucellosis was apparently higher in North Mecha District, in male, married and uneducated human respondents. In conclusion, unlike human brucellosis, the occurrence of small ruminant brucellosis was not detected in the study areas. The detection of human brucellosis in human population can pose a significant public health concern in the study area. Therefore, educating the community about the zoonotic importance of the brucellosis and its transmission mechanisms could help to control brucellosis in humans. This can be successfully implemented through a ONE health approach, in which a synergetic effort among veterinarians and human health experts is required. Besides, this study didn’t explore the association between livestock farming and brucellosis in humans, further comprehensive epidemiological investigation of brucellosis among animals and humans is warranted in the study areas.