Contamination of cereal crops and their products could be a result of inappropriate cultivation techniques as well as disregarding usual agro-technical measures like the seed treatment with fungicides. The aim of the study was to determine the impact of pre-sowing seed treatment on wheat seed infection and contamination of produced grains from the field trial at the Biotechnical faculty (BF) and contamination of crop samples from Slovene farms with conventional and organic type of production. In our laboratory we performed grain incubation on agar with various disinfectants before sowing the grain on the field. We found that seed treatment with fungicides Maxim 050 FS and Vitavax 200-FF had significantly improved the health status (2% infected grains) compared to untreated processed seed (25% infected grains). The effectiveness of both tested fungicides was significantly better (2% infected grains) compared to the Agrostemin and Fitolife preparations, which are allowed in organic farming (15% infected grains). Compared to the untreated seed, treating the seeds with both fungicides and the Agrostemin preparation reduced visible ear contamination with fusariosis during the time of dough maturity. With incubation of grain from our field experiment with different seed treatments, the positive effect of fungicides on the health status of grain yield was confirmed (27% infected grains), compared to sowing of seed that was not treated with disinfectants (34% infected grains). When compared to the control group a positive effect of wheat seed treatment with disinfectants used in organic farming was determined. Furthermore, seed treatment with fungicides had a greater influence on improving the health status of produced grain, compared to the above mentioned preparations allowed in organic farming (29% infected grains). The effect of seed treatment on the health status of the grain was the greatest when using the Vitavax 200-FF fungicide. The percentage of infected grains in laboratory incubation of produced wheat grain on agar, sampled from eight Slovenian farms, ranged from 1.5 to 19.5%. Contamination of sampled grain from organic production (7% infected grains) was comparable with infection of grain from the conventional farming (8.4% infected grains), where the infection ranged from 1.5% to 19.5%. Onesnaženja pridelkov in izdelkov žit so lahko posledica slabe pridelovalne prakse, zlasti neupoštevanja običajnih agrotehničnih ukrepov, med katerimi je razkuževanje semena. Namen raziskave je bil ugotoviti vpliv razkuževanja semena na okuženost semena pšenice pred setvijo in pridelka zrnja iz poljskega poskusa Biotehniške fakultete (BF) ter okuženost vzorcev pridelanega zrnja iz konvencionalne in ekološke pridelave. Pri laboratorijski inkubaciji zrnja na agarju pred setvijo poljskega poskusa na BF z različnimi razkužili smo ugotovili, da tretiranje semena s fungicidoma Maxim 050 FS in Vitavax 200-FF (2 % okuženih zrn) pomembno izboljša zdravstveno stanje v primerjavi z nerazkuženim dodelanim semenom (25 % okuženih zrn). Delovanje obeh fungicidnih pripravkov je bilo statistično značilno boljše (2 % okuženih zrn) od pripravkov Agrostemin in Fitolife, ki sta dovoljena v ekološkem kmetijstvu (15 % okuženih zrn). Razkuževanje semena s fungicidoma in pripravkom Agrostemin je v primerjavi z nerazkuženim semenom zmanjšalo vidne okužbe klasov s fuzariozami v času voščene zrelosti. Pri inkubaciji pridelka zrnja iz poljskega poskusa z različnimi razkužili smo potrdili pozitiven vpliv tretiranja semena s fungicidoma na zdravstveno stanje pridelanega zrnja (27 % okuženih zrn) v primerjavi s setvijo nerazkuženega semena (34 % okuženih zrn). V primerjavi s kontrolo je bil ugotovljen pozitiven vpliv razkuževanja semena pšenice s pripravkoma, ki ju lahko uporabljajo tudi ekološki kmetje. Razkuževanje s fungicidoma je imelo večji vpliv na boljše zdravstveno stanje pridelanega zrnja kot pripravka dovoljena v ekološkem kmetijstvu (29 % okuženih zrn). Vpliv razkuževanja na zdravstveno stanje pridelanega zrnja je bil največji pri fungicidu Vitavax 200-FF. Pri laboratorijski inkubaciji pridelka zrnja pšenice na agarju z osmih slovenskih kmetij smo ugotovili, da je bila okuženost vzorcev pridelanega zrnja iz ekološke pridelave (7 % okuženih zrn) na ravni vzorcev iz konvencionalne pridelave (8,4 % okuženih zrn), pri katerih pa je bil razpon okuženosti od 1,5 % do 19,5 %.