Aquatic vegetation of the mountains and sub-alpine ponds in the Tatra Mountains and adjacent area (Slovakia) has been studied with the aim to provide information about the composition and species richness of macrophytes in relation to environmental factors. Macrophytes were studied in two pond groups: natural ponds of glacial origin and artificial ponds. Simultaneously, eight environmental variables were measured or estimated at each pond. The studied pond groups differed significantly (Mann-Whitney U-test, P<0.01) in almost all recorded environmental variables except for water temperature and pond area. Almost all environmental characteristics showed higher variability in the artificial ponds. In total, 70 macrophyte taxa were found at the study sites consisting of ca 90% of vascular plants and ca 10% of bryophytes. Artificial ponds were characterised by a multi-element vascular plant species group typical for marshy and aquatic habitats of lower altitudes, while Carex rostrata was the only species typical for natural ponds. Species richness differed significantly between the two pond groups, with artificial ponds hosting considerably more species. Species richness of all studied ponds was negatively correlated with altitude and precipitation; a positive relationship was found with water pH and conductivity, air temperature, and degree of human impact. The species composition of ponds was affected mainly by precipitation and human impact.