We monitored the breeding success of the Common Cuckoo (Cuculus canorus) in four reed habitats (e.g. clay pits, marsh and fishponds, small canals and large canals) in northwestern Vojvodina (Serbia) between 2009 and 2011 (three breeding seasons). A total of 596 Great Reed Warbler (Acrocephalus arundinaceus) nests were found and monitored. The overall parasitism rate for the study area was 0.127, which was calculated from the number of parasitized nests (76) divided by the total number of Great Reed Warbler nests (596). The parasitism rate did not vary with the total number of Great Reed Warbler nests at a study site. The number of parasitized and successful parasitized nests showed significant negative relationship, which means more parasitized nests resulted with more brood lost. The parasitism rate varied significantly among habitats but not among years while the number of successfully parasitized nests differed among both habitats and years. Parasitized nests found in small and large canals showed the highest reproductive success of Cuckoos. Loss of parasitized nests through predation and bad weather circumstances was relatively high in this study compared to other areas.Od 2009. do 2011. godine (tri gnijezdeće sezone) provedeno je istraživanje o uspješnosti gniježđenja obične kukavice (Cuculus canorus) na četiri različita trščana staništa (iskopine, močvare i ribnjaci, mali i veliki kanali) u sjeverozapadnoj Vojvodini (Srbija). Parazitiranje kukavice praćeno je u 596 gnijezda velikog trstenjaka (Acrocephalus arundinaceus). Stopa kukavičjeg parazitiranja za cijelo istraživano područje iznosila je 0.127, a izračunata je tako što je broj parazitiranih gnijezda (76) podijeljen s ukupnim brojem nađenih gnijezda velikog trstenjaka (596). Pojedinačno po istraživanim lokacijama broj parazitiranih gnijezda nije varirao zajedno s ukupnim brojem gnijezda velikog trstenjaka. Broj parazitiranih gnijezda je bio u negativnoj korelaciji s brojem uspješnih parazitiranih gnijezda, tj. što veći je broj parazitiranih gnijezda, više je propalih. Stopa parazitiranja varirala je značajno između staništa, ali ne između godina, dok je broj uspješno parazitiranih gnijezda značajno varirao između staništa i godina. Parazitirana gnijezda nađena na malim i velikim kanalima su rezultirala s najvišom reproduktivnom uspješnosti kukavice. Broj propalih gnijezda zbog predacije i loših vremenskih prilika u ovom je radu, u usporedbi s rezultatima drugih izvora, relativno visok
