The first national survey of otter distribution in Slovakia was carried out in winter 2007/2008. The mapping was done using the modified standard IUCN/OSG methodology. Results were obtained from 275 "Databank of Slovak Fauna (DSF)" quadrates (64 % out of 429 DSF quadrates). The second mapping was carried out in winter 2008/2009 in 54 DSF quadrates (12.6 % out of 429 quadrates). In total, this covered 292 quadrates (88.7% out of checked quadrates; 61% out of all 429 quadrates in the Slovak Republic); in 36 quadrates (1% and 8%, respectively), no otters were recorded. The third one-off otter mapping on the whole Slovak territory (in all 429 quadrates) was carried out in summer 2010 with the “standard” method: 349 quadrates (81.4%) were positive and 80 quadrates (18.7%) were negative. The otter occurs in most parts of the country with the exception of parts of the Western and South-Eastern lowlands of Slovakia. Otter signs were found in all types of water bodies and channels of all sizes and in different types of reservoirs (dams, ponds, fishponds) in various land cover classes.