Changes in antioxidant and biochemical constituents were studied in guava fruit cv. Apple colour to determine the optimum time of harvest. Fruits were analysed at 15 days interval at 30, 45, 60, 90, 105,120, 135 and 150 days after fruit set. Continous increase in TSS content was observed in guava cv. Apple Colour at different growth intervals (30 to 150 days) . Ascorbic acid content in guava varieties exhibited peculiarity, which firstly, increased from up to 120 days and then decreased at 150 days while titratable acidity in guava varieties increased from 30 days to 150 days and then decreased from 120 days to 150 days. Total sugars, reducing sugars and total carotenoid showed continous increasing trend from fruit development till ripening in guava cultivar. While anthocyanin content increased from 105 days to 150 days only.