Introduction. The use of fluoroquinolones is associated with prolongation of the QT interval on the cardiogram and increased risk of ventricular tachycardia. To study the mechanism of the cardiotoxic effect of fluoroquinolones and to develop methods of its prevention it is necessary to create models on laboratory animals. The aim of the work was to analyze the effect of fluoroquinolones on the electrocardiographic parameters of laboratory rabbits. Materials and methods. 20 rabbits were divided into 3 groups: 6 animals were control, 7 animals received ciprofloxacin 150 mg/kg for 14 days orally, 7 animals received levofloxacin 150 mg/kg for 14 days orally. Electrocardiography was performed before and after 14 days of drug exposure. P wave width, PQ interval, QRS complex, QT interval, corrected QT (QTc), RR interval were analyzed. Data are presented as median and interquartile range. Results. Rabbits treated with ciprofloxacin showed a prolongation of the QTc interval compared with controls (QTc according to Bazett 306.2 (285.8; 319.8) versus 271.1 (255.2; 285.8) ms, p = 0.022; QTc according to Frederick 241.4 (225.3; 245.5) ms versus 219.1 (201.1; 225.3) ms, p = 0.022), as well as P wave shortening during the experiment (from 55.0 (50 .0; 70.0) ms to 40.0 (35.0; 50.0) ms, p = 0.027). Discussion. Observed electrocardiographic changes indicate the ability of ciprofloxacin to accelerate atrial conduction, slow down ventricular myocardium repolarization and increase the risk of arrhythmias. Conclusions. Oral ciprofloxacin administration at a dose of 150 mg/kg/day for 14 days simulates cardiotoxic effect in laboratory rabbits.