Observations were conducted over 5 years ( 1989-1993) in natural stands in south-eastern Poland. The aim of this research was to examine relations between Sitona weevils and wild-growing leguminous plants. In total, 28861 weevils (Curculionidae) were collected from which 10425 (36.1%) belonged to the Sitona genus. The most common species was S. lineatus L., which was collected in each examined stand. Adult forms of this weevil occurred in large numbers especially on Vicia sp., S. humeralis Steph. was dominant on Medicago sativa, S. cylindricollis Fahrs. grew on Melilotus albus, S. sulcifrons Thunbg. was numerous on Trifolium pratense and T. alpestre. S. waterhousei Walt. occurred on Lotus corniculalus whereas S. suluralis Steph. was dominant on Lathyrus pratensis. Coronilla varia was dominated by S. languidus Gyll. and Ononis arvensis was dominated by S. suturalis. So, we can say that every leguminous plant is accompanied by at least one specialised Sitona species, which can essentially reduce the number of root nodules and consequently decreased the quantity of fixed atmospheric nitrogen in soil.