In order to improve the comprehensive utilization of major by-products in apple-juice processing, the components, antioxidant and antimicrobial activities of oil in two species apple seeds, Fuji and New Red Star, were investigated. The Soxhlet extracted oil content of apple seeds raged from 20.69 to 24.32 g/100 g. The protein, fiber and ash contents were found to be 38.85-49.55 g/100 g, 3.92-4.32 g/100 g and 4.31-5.20 g/100 g, respectively; the extracted oils exhibited an iodine value of 94.14-101.15 g I/100 g oil; refractive index (40 degrees C) was 1.465-1.466; density (25 degrees C) was 0.902-0.903 mg/ml; saponification value was 179.01-197.25 mg KOH/g oil; and the acid value was 4.036-4.323 mg KOH/g oil. The apple seed oils mainly consisted of linoleic acid (50.7-51.4 g/100 g) and oleic acid (37.49-38.55 g/100 g). Other prominent fatty acids were palmitic acid (6.51-6.60 g/100 g), stearic acid (1.75-1.96 g/100 g) and arachidic acid (1.49-1.54 g/100 g). Apple seed oil was proven to possess interesting properties, emerging from its chemical composition and from the evaluation of its in vitro biological activities. The apple seed oil was almost completely active against bacteria, mildews were less sensitive to apple seed oil than yeasts, and the minimum inhibitory concentration (MIC) of apple seed oil ranged from 0.3 to 0.6 mg/ml. The observed biological activities showed that the oil had a good potential for use in the food industry and pharmacy.