Studies were conducted in 2005–2007 on an existing field plantation of American ginseng in Krasnystaw (Lubelski region). The object of the studies was the soil from the American ginseng cultivation where two kinds of mulch were used, i.e. oat straw and mineral mulch Agran. Microbiological analysis of the soil of particular experimental combinations showed differentiated populations of microorganisms. On average, the most colony-forming units (CFU) of bacteria in total were obtained from the soil taken from ginseng cultivation after using mineral mulch as compared to the combination with oat straw. Similar results of CFU were obtained in the case of Bacillus spp. and Pseudomonas spp. On the other hand, the most CFU of fungi were isolated from the soil samples taken from the combination after the use of oat straw. The most frequently isolated fungi regarded as pathogenic to ginseng plants were: Fusarium spp., Cylindrocarpon spp., Phytophtora sp., Pythium irregulare, Rhizoctonia solani, Sclerotinia sclerotiorum and Altenaria alternata.