Objectives The aim of this paper is to determine the presence of pesticides in citrus fruits available in supermarkets in Croatia as well as to estimate the danger of harmful effects on human health. Material and Methods The practical part of this work consisted of testing citrus fruits - orange, grapefruit and lemon, originating from Croatia and imported. Some samples of fruits were tested as the whole fruits while their peel and pulp were tested separately. There were thirty samples for analysis. Using analytical equipment for identification and quantitative determination of pesticides, the quantity of pesticides in samples of particular citruses was defined. For this study the combined technics of gas chromatography and tandem mass spectrometry (GC-MS/MS) was used, and samples were analysed on 185 active substances. After the quantification was done, it was established if the concentrations of pesticides identified in analysed samples can have harmful effects on human health and if these products correspond to the legislative which approves placing particular products on the market. Results Active substances identified in analysed samples are imazalil, propiconazole, ophenylphenol and chlorpyrifos. Identified concentration of active substances in analysed products is not greater than maximum residue levels. The initial idea was to analyse pesticides which are used in postharvest treatment, but the results of analyses show the presence of some other pesticides which are used for other purposes. This is the evidence that pesticides are used in different stages of producing citrus fruits. Conclusion The samples analysed in this research are safe for health, which means that they don't exceed legally permitted maximum residue levels of pesticides in these products and there is no danger of harmful effects on human health.