This research compared the numbers and types of different Mycobacterium species in soil samples taken from 2 areas of Golestan province, Islamic Republic of Iran, 1 with a high prevalence of tuberculosis and 1 with a low prevalence. From 220 samples, 91 grew positive cultures (41.4%) and 161 different strains were diagnosed. The most common species isolated were Mycobacterium fortuitum, M. flavescens and M. chelonae. The frequencies of environmental Mycobacterium in the low-prevalence area were much higher than in the high-prevalence area, perhaps due to different environmental factors.