Except of benefits for human population, several industrial activities have a negative consequences i.e. increasing of heavy metal content and changes in diversity of living organisms in environment. The aim of this work was to examinated the influence of high content of heavy metals on microbial diversity of soil. Researches was conducted at locations of former factory 'Rog' (Ljubljana, Republic of Slovenia), by taking of four samples of contaminated soil, while the control was uncontaminated soil sample. Determination of microbial diversity (abundance of bacteria, fungi and actinomycetes) was performed using the standard methodology. The results of research showed that abundance of microorganisms depends on location and presence/absence of contamination. In control treatment abundance of all examinated groups of microorganisms was higher compared with other samples. The bacterial number in contaminated samples was from 1.21 to 6.88x106 CFU/g, the number of fungi was from 1,08 to 30,30x103 CFU/g, while actinomycetes number from 302,15 to 381,82x103 CFU/g. In control treatment, bacterial number was 17,45x106 CFU/g, fungi number 54,02x103 CFU/g and actinomycetes number 481,91x103 CFU/g. These results confirms the importance of microbial diversity research on contaminated locations and potential applications of bioremediation technologies on locations of former factory 'Rog'.