Research was initiated with the objectives to determine the prevalence of fasciolosis; impact of liver fasciolosis species through liver condemnation in Mizan-Aman abattoirs, Mizan-Aman town of Bench-Maji Town (South Western Ethiopia). Postmortem examinations were conducted on 384 slaughtered cattle during the study period. 15.58% Prevalence of Fasciolosis observed in this study and statistically significant difference in the prevalence rate of the two species of Fasciola (P= 0.000). Of the 60 Fasciola positive livers from Wacha-Maji origin animals 10.13%, 1.04 %, 0.78 % and 3.64 % were for F. gigantica mature fluke, immature fluke and F. hepatica respectively, so that F. gigantica is more prevalent in Wacha-Maji area (10.13%) than Fasciola hepatica (3.64%). The overall species identification revealed that F. gigantica was more prevalent (10.13%) as compared to F. hepatica (3.64%). Pathological lesions were classified in to three based on degree of pathological lesions observed. Out of the 60 Fasciola infested livers 20 (33.33 %), 11 (18.33%) and 29 (48.33%) were severely, moderately and lightly affected respectively. Finally, a few point of recommendation was forwarded.