Khasi Mandarin (Citrus reticulata Blanco) is a commercially popular and nutritionally rich subtropical citrus species in the North Eastern Himalayan region of India including Assam. In the present study during the analysis of the biochemical constituents of Mandarin juice among the seven different districts i.e. Tinsukia, Lakhimpur, Jorhat, Golaghat, Karbi Anglong, Dima Hasao and Kamrup with accession number “AKM”( Assam Khasi Mandarin) from 01 to 07 for districts respectively and T1 to T5 for plant number. The highest TSS of 11.9 0Brix was recorded in AKM07T2 and the lowest was recorded in AKM06T2 i.e. 6.22 0Brix. The highest pH of 5.98 was observed for AKM03T1 and the lowest (3.26) for AKM02T1. The titrable acidity of fruits recorded a mean of 0.66% was recorded for AKM02T1. Similarly, the lowest (0.32%) was recorded for AKM06T1. The TSS: Acid ratio for all the accessions recorded a mean of 13.82 within the range of 7.92-23.33. On the other hand, the total sugars for all the accession were within the range of 5.03- 5.98% with a mean of 5.43%. The highest ascorbic acid content (49.98) was recorded for AKM01T2 and the lowest of 24.99 was documented for AKM06T2. The total antioxidant activity of all the accessions were within the range of 0.08-0.24 with a mean of 0.16. The highest value for total flavonoid content was recorded for AKM05T1 (9.56) and the lowest for AKM04T1 (4.34).