Effects of temperature, concentration of NaOH solutions and immersion time on caustic peeling of apples were studied. NaOH solutions of 6, 9, 12 and 15% were heated to 60, 70, 80, and 90 degrees C at various immersion times were used, until more than 98% peeling was achieved. Temperature of caustic solution versus immersion time plot showed a linear trend. Concentration of the caustic solution changed linearly with respect to immersion time. Increase in both temperature and concentration reduced the immersion time needed for efficient peeling.