Abstract: The distribution and abundance of Ground beetles (Coleoptera, Carabidae) in arablecrops was examined to study the effects of different agricultural measures on biodiversity. Theaim of the study was to determine differences in Ground beetle fauna between treated anduntreated barley fields. The study was conducted during the 2009 vegetation season in six barleyfields located in the central part of continental Croatia. In three fields, chemical control ofOulema melanopus L., the main barley pest, was done using chlorpyrifos-methyl in a dosage of600g a. i. per ha. Applications were done in the end of May. Beetles were collected from midApril till the end of August a period of five months by placing 3 modified pitfall traps in eachfield. All Ground beetles were identified to species, if possible, or genus. The abundance andfrequency of Ground beetle fauna was calculated according to Balogh formula and ANOVA testswere performed to identify possible differences between treated and untreated barley fields interms of total numbers of ground beetle collected, total numbers of taxa identified and numbers ofspecimens of two most abundant species.Twenty two different genus and species were determinate on both type of field. The mostabundant species classified as eudominant was Pseudoophonus rufipes (De Geer 1774). Averageabundance reached 51.4% and 47.7% on untreated and treated fields, respectively. Averagefrequency of this species was 51.0% on untreated and 42.0% on treated fields, respectively.Pterostichus melanarius (Illiger 1798) was the second most abundant species with 30.5% of thecollected beetles on untreated and 18.4% on treated fields, respectively. Average frequency of P.melanarius reached 30.0% on untreated and 24.0% on treated fields, respectively. The statisticalanalyze of collected fauna shows that there was no significant difference among total number ofestablished species and/or genus. The number of specimens collected did not differ significantlybetween treated and untreated fields both for the two eudominant species and for the wholecarabid beetle community.