Soil is a habitat for various groups of microorganisms, such as bacteria, actinobacteria and filamentous fungi. Their number and biodiversity affect on the quality, productivity and biological activity of the soil. Microbiota occurrence is affected by the soil physical, and chemical properties, as well as by soil fertility level, and the way it is used, especially by agricultural practice. The aim of this study was to determine the number of bacteria, actinobacteria and fungi in four arable soils of Lublin province (two Cambisols, Chernozem and Leptosol) with different physico-chemical properties. Relationships between soil microbiological and physico-chemical parameters were also detected. The number of selected groups of microorganisms was determined by the serial dilution method and pour-plate technique. Plates with culture of bacteria/actinobacteria were incubated for 3 days at 28°C, and with fungi for 5 days at 25°C. Determination of physico-chemical soil properties was carried out using procedures used in soil science. Numbers of microorganisms were presented in cfu kg-1 d.w. of soil. The obtained data were correlated at three levels of significance: α = 0.05, 0.01, and 0.001 using Statistica software ver.13.3 (StatSoft, Kraków, Poland). It was found that Leptosol were the richest habitat for bacteria (2.37 × 1010) and actinobacteria (5.01 × 108). It was related to the soil pH (6.9) and content of P, Mg, K, Ca. In comparison to Leptosol, the number of microorganisms (bacteria and actinobacteria respectively) was lower in both Cambisols (in total: 31.2%, 71.1%) and Chernozem (43.1%, 97.4%). Chernozem, that was rich in organic matter (2.5%) with slightly acidic pH (5.0) was characterized by the greatest number of fungi (7.81 × 108). Number of bacteria and actinobacteria was the lowest in Cambisols. The lowest number of fungi was detected in Leptosol. Based on the analysis of r-Pearson correlation coefficient, it was found that the number of bacteria (p <0.001) and actinobacteria (p <0.05) were strongly positively correlated with the content of organic carbon, total nitrogen, assimilable phosphorus and potassium. The number of fungi were significantly negatively correlated only with content of total carbon, carbonates, and elements, such as calcium and magnesium. Number of bacteria, and actinobacteria were significantly negatively correlated with the sand fraction (p <0.05), and strongly positively (p <0.001) with the loam and silt fraction.