A study was conducted in order to determine the comparative efficacy of Triclabendazole, Oxyclozanide and Nitroxynil against Fasciola sp. infestated bovines (cattle and buffaloes) and their effect on various blood parameters (WBC, RBC, Hb, HCT and MCHC). For this purpose, 40 infected animals were selected. After dividing them randomly in four groups of 10 animals each, drug was administered to first three groups whereas last one was kept under positive control for comparison. Study revealed that Triclabendazole was most effective drug of all three in both cattle and buffaloes with efficacy of 97.92% and 100%, respectively; Oxyclozanide was 2nd most effective with efficacy of 96.87% and 97.05% % whereas Nitroxynil remained at last with efficacy of 93.47% and 92.15% at 21st day post-medication. A slight increase of egg counts was observed in positive control groups of both animal categories. Blood parameters of healthy and Fasciola infected animals (cattle’s and buffaloes) were compared; specifically, Mean±S.E.M value of WBCs (white blood cells) in infected animals had increased compared to healthy animals. At the same time, significant decrease was observed in RBCs (red blood cells), Hb (haemoglobin), and HCT (hematocrit) in Fasciola infected animals compared to health animals but no significant difference was observed in MCHC (meancorpuscular hemoglobin concentration) quantity within both animal categories.