Kinnow fruits were collected from the 15 year old orchard of ICAR-Central Institute for Arid Horticulture (CIAH), Bikaner at three different time of harvesting such as immature (early), fully mature (mid) and over-mature (late) as treatments with five replications under Completely randomized design. Observations made on fifteen different parameters, which include seven physical and eight biochemical traits. Assessment of nutritional quality of Kinnow revealed the impact of each stages of fruit maturity on the quality aspect of this citrus species. Important nutritional quality parameters viz TSS (11.8°Brix), vitamin –C (49.0mg/100ml), total sugar (8.1%), reducing sugar (4.9%), non-reducing sugar (4.1%) are found to increase as the fruits progress towards maturity. Only antioxidant activity (2.1mMTE/L) and total phenolic content (2060.4µg/100g) revealed phenomenal changes decreasing at mid maturity and again increase in the later stage of full maturity. Although the significant difference obtained in physical and biochemical changes between the mid and late maturity stage, the maximum attainment of fruit nutritional quality at the late maturity or full ripe stages of the mandarin suggesting the right stage of consumption of Kinnow fruits.