Abstract: This experiment has been conducted to study antioxidant activities and biochemical changes in round as well as long cultivars of brinjal. Results showed that maximum protein content, amino acids, important minerals (Ca, P, K) and crude fibres were recorded in Pusa Purple Round Pusa Purple Long. Maximum phenolic content of brinjal fruit in round varieties was obtained in Pusa Purple Round followed by Pant Rituraj and NDBH-1 (86.13 mg/100 g). Phenolic content was maximum in Pusa Purple Long followed by Pusa Kranti and NB-2 in long varieties and Pusa Purple Round in round varieties. A linear relation between the total phenolic content and DPPH activities of the extracts was observed. Antioxidant activity of brinjal fruit was noticed between (182.01-234.13 μg) in round varieties and (172.11-219.92 μg) in long varieties. Maximum antioxidant activity of brinjal fruit in round varieties was obtained in Punjab Bahar followed by Pusa Purple Round and NB-1. However in long varieties of brinjal fruit it was maximum in NDBH-2 followed by Pusa Purple Long and NB-1. While, lowest activity was recorded in round variety NDBH-1 and Pant Samrat in long variety. On the basis of biochemical investigation, it can be concluded that brinjal is very nutritive and useful vegetable because it is rich source of protein, minerals, crude fibre, phenolic content, antioxidant activity and important essential amino acids.