Soil microbes show positive ecological interactions which promote nutrient recycling, decomposition and plant growth. To study the effect of different fertilizer sources on soil organic matter and soil microbial population in broccoli field, an experiment was conducted at Agriculture and Forestry University, Chitwan, Nepal from September 2015 to February 2016. The research consisted of ten treatments viz; recommended NPK fertilizer, Farmyard manure (FYM), Vermicompost (VC), Cow urine (CU), Bio

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... rganic fertilizer (BOF), (NPK 50% + FYM 50%), (FYM 50% + CU 50%), (FYM 50% + VC 50%), (FYM 50% + BOF 50%) and (25% FYM + 25% VC+ 25% CU+ 25% BOF) in randomized complete block design replicated three times. The study revealed that highest soil organic matter was recorded in FYM (50%) + vermicompost (50%) treatment (2.85%) which remained statistically similar with all other organic treatments. The recommended NPK treatment had significantly lowest SOM (2.06%). The highest bacteria population (43.6 x 10 7 cfu/g) and highest fungi population (11.0 x 10 6 cfu/g) were observed in treatment consisting all organic fertilizer sources (25% FYM + 25% VC+ 25% CU+ 25% BOF). In recommended NPK treatment, the bacteria and fungi population were 4.10 x 10 7 cfu/g and 7.1 x 10 6 cfu/g in 10 -6 dilution respectively. But, in the treatments consisting organic fertilizer sources, bacteria population ranged from 2.93 x 10 7 cfu/g to 43.6 x 10 7 cfu/g and fungi population ranged from 7.33 x 10 5 cfu/g to 11.0 x 10 6 cfu/g in the same dilution respectively. Positive regression relation was also observed in between soil organic matter and soil microbes. Therefore, organic fertilizer sources supported for soil organic matter enrichment and promotion of bacteria and fungi population in the soil in comparison to chemical fertilizers.