In this research, reducing activity of Turkish propolis on patulin production of Penicillium expansum in apple juice was investigated. To compare the antifungal activity of propolis, sodium benzoate was also used as a positive control. Different concentrations of propolis (0.1, 1 and 2mg/mL) and sodium benzoate (0.35mg/mL) were added into apple juice after P.expansum inoculation. Apple juice samples were then mixed with propolis, and patulin content was determined in 1st, 24th and 48th hours. High-performance liquid chromatography equipped with diode array detector which is a reliable equipment for the determination of patulin in apple juice, were used after clean-up procedure. Considerable patulin reduction was achieved with the addition of propolis in the apple juice. The best result was obtained at 2mg/mL propolis added group for 48h incubation. It was concluded that propolis can be used as a natural antifungal agent for P.expansum inhibition instead of chemical preservatives. Practical Applications Propolis is a natural honeybee product, and it is rich in functional bioactive compounds. It can be used to inhibit the patulin-producing microorganism. The inhibitory effect of propolis in the apple juice showed that it is an effective natural inhibitor.