During the five years (1991-1995) mostly free living small mammals were examined serologically for the presence of antibodies to leptospira. Serological examinations were used by Kmety and Bakoss (1978). Altogether, 2 493 individuals of 22 species were examined, an important part of host material (69.6%) was caught in two lowland areas which are intensively cultivated landscapes (East Slovakian Lowland and Kosicka kotlina basin). The remaining material comes from submontane areas with less agricultural activities. Apodemus flavicollis, A. agrarius, Clethrionomys glareolus were the most frequently examined species. Antibodies to leptospira were demonstrated in 123 mammals (i. e. in 5.0% of hosts) of eleven species. The highest percentage of positive hosts were recorded in 1993 (8.8%) and the lowest (2.6%) in 1995, but the examined samples were different in size and structure of host species. In six most dominant species higher values of antibodies to leptospira were detected in Microtus arvalis (9.2%), followed by Apodemus flavicollis (5.6%), A. agrarius (5.4%) and A. microps (4.9%). The lowest values were found in Clethrionomys glareolus (2.5%) and Sorer araneus (2.3%). In examined hosts we found antibodies to six serovars of leptospira. The most frequently observed antibodies were to leptospira of the serovar L. grippotyphosa (63.2%) and leptospira of the serovar L. sejroe (26.4%). We recorded nonsignificant differences between the values of prevalence to antibodies in small mammal communities from lowland and submontane areas, resp. Our results confirmed differences in the leptospira serovar structure in small mammals of Bohemia and Slovakia, they were connected with different historical development of boths areas. Comparing our results with previous examinations (about 20 years ago) in small mammals from eastern Slovakia, a decline of positivity and lower number of leptospira serovars were recorded.