Sodium benzoate is often chosen for the manufacture of liquid food supplements as preservative due to its antimicrobial effect against a large number of microorganisms. Permissible sodium benzoate amount in liquid food supplements is up to 2000 mg/l. Methods . For investigation six liquid food supplements, containing sodium benzoate were randomly chosen. Analysis was performed using CAMAG Twin Chamber, TLC Silica Gel 60 F254 glass plates, solvent system (chloroform – ethanol 9:1) and the UV-light (254 nm) for visualization. Results. Methods for visualisation and solvent system were selected using the reference solutions. Sodium benzoate was identificated by R f = 0.76, it’s quantity was determined by calibration. Validated methodics was adapted for identification of sodium benzoate in liquid food supplements. The amount of sodium benzoate in all investigated objects was analysed and did not exceed the permissible amount. Conclusions. Selected methodics are suitable for qualitative and quantitative evaluation of sodium benzoate in liquid food supplements