Fluorquinolones (FQ) are a class of antibiotics that manifest a broad spectrum of antibacterial activity [1]. Due to their extensive usage, fluoroquinolones may enter the aquatic environment what constitutes a danger for the ecosystem and human health by causing the increase and spread of bacteria drug resistance [2]. This is why it is very important to solve the problem of deep FQ oxidation by applying advanced oxidation processes (AOPs). It uses UV, UV/H₂O₂, O3/UV, Fenton, photo-Fenton systems and represent a cyclic process with regeneration of Fe₂+ ions. These systems are the promising treatment options for wastewaters [2,3]. The purpose of this work was to study the kinetics of oxidation of four FQs – ofloxacin (OF), levofloxacin (LFX), ciprofloxacin (CPF) and moxifloxacin (MOX) under UV irradiation and by the UV-H2O2 system. During the work the spectrophotometric method and „DRT-1000” lamp as a irradiation source was used. Antibiotic concentrations varied from 12.5 to 30 mg/l. It was established that under the UV irradiation the oxidation process of each drug proceeds as a zero order reaction (what is characteristic for photochemical reactions). Antibiotics oxidation by the UV-H₂O₂ system proceeds with a considerably higher rate than under UV irradiation. In the UV-H₂O₂ system the total degradation of drugs occurs. It was determined that the reaction rate increases with the increase of oxidant and substrate concentration. Oxidant concentrations varied from 5*10-5 to 5*10-4. It was established that the reaction orders with respect to antibiotics have fractional values less than one, being in the range from 0.17 to 0.56. It was found that the reaction orders with respect to H₂O₂ also have fractional values less than one, varying from 0.49 to 0.69. The reaction rate dependence on the pH was studied. It was determined that at the pH increase the reaction rate slightly increasing. The reaction orders with respect to H+ ions have negative fractional values. The rate equations for MOX and CPF oxidation by UV-H₂O₂ were established:The data obtained allowed us to conclude that the whole process of photolysis of substrates in the presence of H2O2 can be formed by the 4 main steps.