Matters related to the application of insecticide in the various crops need to be highlighted due to the impact of this practice on the environment, instigating the need for studies to measure their effects on soil microorganisms, which are responsible for soil irreplaceable functions. Microbiological indicators are very sensitive and reflect the environmental status or sustainability condition of the ecosystem. This work aimed to study the effects of the application of the insecticide Metomil on the soil microbiota through the microbiological bioindicators, analyzing the amount of colony forming units (CFU), the Carbon content of the microbial biomass (C-MB), the microbial soil respiration, the metabolic quotient (qCO2) in the area with a history of six years of corn cultivation. The experiment was conducted in the laboratories of microbiology and chemistry II belonging to the Faculties of Exact and Technological Sciences of Santo Agostinho. The results showed that the microbiological indicators were affected during the analyzed period. The Metomil decreased the number of microorganisms in the soil, decreased the microbial activity, however, did not present significant difference to the values of qCO2, where both the control and impacted soil presented a stress level. It can be concluded that the studied insecticide promoted negative effects on the microorganisms, resulting in the loss of the biotic quality of the soil.