Vermicompost as soil organic amendment increase the yield crops because improve the soil structure, the water retention capacity, the microbial biodiversity and thereby its metabolic activity. Vermicompost is also thought to reduce the pesticide pollution. The vermicompost selected was composed of “alperujo” which is largest organic residue in olive oil production. Agricultural soil was 5% amended twice and incubated for 3 months. A 3µg g-1 agricultural dosage of Diuron was applied to amended and unamended soils. The effect of alperujo vermicompost on dehydrogenase activity, the biodiversity and estimated bacterial density, the density of protocathechuate-degrading bacterial community and diuron persistence at different times were evaluated. Following the total isolation of the DNA, the quantitative Polymerase chain reaction (qPCR) for both the 16S rDNA and pcaH gene was carried out and the Automated Ribosomal Intergenic Spacer Analisis (ARISA) was performed to estimated bacterial diversity. After 90 days of incubation, both bacterial density and structure were greater in the soils amended with vermicompost and diuron. These results correlate with dehydrogenase activity, indicating that this amendment had a greater impact. However, these results were not significantly related to pesticide loss. This can by explained by diuron availability due to the application of vermicompost.