A 12-wk study was conducted to investigate the effect of feeding ratios of coconut and palm kernel oils (CNO-PKO) on the rumen microbial population of grazing cattle. The experiment was carried out at Cattle Production Venture Farm, Federal University of Agriculture Abeokuta, Ogun State, Nigeria. Twelve (12) White Fulani cattle with average weight of 164 ± 2.81 kg were allotted into 4 treatments of CNO-PKO administration (0 g/day (control), 100:50 g/day (HCLP), 50:100 g/day (LCHP) and 75:75 g/day (ECP) in a completely randomized design. Rumen fluid samples were obtained from each cattle after oil administration period and microbial population was determined by total direct count of protozoa and fungal zoospores while bacteria analysis was carried out using anaerogen packs. Data were analyzed using one-way ANOVA (SPSS Statistics 20). The results showed that rumen bacteria in the genus Bacteroides spp. was not significantly (P > 0.05) affected by the treatments. Clostridium spp. count of those maintained in the control group recorded the greatest (P < 0.05) number with 6.08 × 10⁶ cfu/mL while the least (P < 0.05) was recorded from cattle maintained on HCLP administration with 2.35 × 10⁶ cfu/mL. Lactobacillus spp. count of cattle maintained in the control group and those on ECP administration recorded greater (P < 0.05) counts of 0.20 × 10⁶ cfu/mL and 0.15 × 10⁶ cfu/mL respectively while lesser (P < 0.05) counts were obtained from cattle maintained on HCLP and LCHP with both recording 0.05 × 10⁶ cfu/mL. Rumen fungi count increased (P < 0.05) with LCHP administration recording 0.60 × 10⁶ cfu/mL while the least (P < 0.05) was recorded with HCLP administration (0.10 × 10⁶ cfu/mL). Rumen protozoa population of cattle was significantly (P < 0.05) reduced with the greatest (P < 0.05) count obtained from cattle maintained in the control group recording 755.99 FEC/g while the least (P < 0.05) was obtained from cattle maintained on ECP administration recording 0.00 FEC/g. Feeding 75 g/d each of coconut and palm kernel oils to grazing cattle reduced the protozoa population of the rumen and might therefore be employed as rumen modifier for methane mitigation.