In the year 2003, the occurrence of arbuscular mycorrhizal fungi (AMF) of the phylum <i>Glomeromycota</i> in cultivated and uncultivated soils of the Lubuskie province was investigated. The occurrence of AMF was examined based on 56 root and rhizosphere soils collected under 7 species of cultivated and uncultivated plants growing in 28 localities. Spores of AMF were isolated from both field-collected samples and trap cultures. They were revealed in 100% of field soils and 93.8% of trap cultures and represented 7 of the 8 recognized genera of the <i>Glomeromycota</i>. The arbuscular fungi occurring distinctly more frequently in the soil and root samples examined were members of the genus <i>Glomus</i>. The species of AMF most frequently occurring in cultivated soils of the Lubuskie province were <i>G. claroideum</i>, <i>G. constrictum</i>, <i>G. deserticola</i> and <i>G. mosseae</i>, whereas <i>G. claroideum</i>, <i>G. constrictum</i>, <i>G. deserticola</i>, <i>G. mosseae</i>, and <i>S. dipurpurescens</i> were more frequently found in uncultivated sites. The analysis of similarity of the species composition of AMF populations in sites of the Lubuskie province and the Western Pomeranian province earlier examined showed that (1) the occurrence in Poland of most taxa of these fungi detected in the study presented here is even and does not change with time, (2) the communities of AMF area are stable, despite the arduousness resulting from the agricultural and chemical practices conducted, and (3) the species diversity of the plants cultivated in a long period of time has no influence on the species composition of populations of AMF.