Mites harmful to stored grains represent a significant threat to the quality and health safety of grain products and can cause significant economic losses, as well as health problems for humans and animals. Identification of mite species is a key step in understanding their biology and planning and implementing effective control strategies. Effective strategies for controlling mites in warehouses are based on the application of preventive hygiene measures, regular monitoring of grain for the presence of pests, or the principles of integrated protection. The aim of this research was to determine the presence and abundance of harmful mite species on stored grains in storage facilities in the area of Sisak - Moslavina County and the City of Zagreb. Six warehouses were sampled and six grain samples were processed. The mite species Acarus siro L., Lepidoglyphus destructor Schrank and Tyrophagus sp. were identified in the samples, which are already known as pests of grains in the Republic of Croatia. The number of mites (0 - 868) determined in the samples is a reflection of the storage conditions and the preventive and curative control measures taken.