AbstractSamples of 24 house fly (Musca domestica L.) populations were collected from animal farms in Hungary in 1990 and kept in the laboratory to determine their susceptibility to different types of insecticide: organochlorines, organophosphates, carbamates, pyrethroids, macrocyclic lactone and insect growth regulators.The adulticides were tested with topical bioassay in all 24 populations, the larvicides were studied with treated larval medium in 16 populations. The data were expressed as LD50 and LC50 values (ng fly −1 and mg kg −1 larval medium respectively).The percentages of populations which had resistance ratios > 10 at LD50 or LC50 were: 63% to DDT, 50% to methoxychlor, 13% to lindane, 83% to malathion, 63% to trichlorfon, 4% to propetamphos, 96% to dioxacarb, 46% to propoxur, 4% to methomyl, 13% to pyrethrum, 96% to bioresmethrin, 63% to permethrin, 58% to cypermethrin, 79% to SK‐80, 79% to deltamethrin, 38% to invermectin, 0% to diflubenzuron, 0% to cyromazine.Correlation analysis showed a high degree of positive correlation among the adulticides except for ivermectin, bioresmethrin and SK‐80. No cross‐resistance was found between the larvicides and the conventional adulticides.Differences of insecticide resistance levels among the populations surveyed were studied by principal component and factor analysis. A fairly good relationship between resistance status and control practices used on farms was revealed. The populations originating from those farms where the application of adulticides had been frequent or regular and where high resistance was shown to most chemicals could be separated from the others.