: Tea leaf envelops basic segments like caffeine, polyphenol, lipid and so forth. The examination was led to discover the basic constituents in green and oolong tea from matured tea leaves during the time of 2012. Tea leaves with various culled matured were gathered from Lackatoorah Tea Home at Sylhet region in Bangladesh. Gathered leaves were processed to make alluring examples for biochemical examination in the research facility of Branch of Nourishment Engineering and Tea Innovation, SUST. Results uncovered that the basic constituents like dampness, caffeine, polyphenol, lipid, protein, debris, ascorbic corrosive, causticity and pH esteem in green tea produced using diverse matured leaves were found marginally higher than oolong tea, ran from 6.38±1.06 to 3.49±0.59%; 4.91±0.82 to 1.49±0.24%; 30.88±5.15 to 18.23±3.04%; 7.50±1.25 to 9.58±1.59%; 13.15±2.19 to 17.33±2.88%; 3.87±1.65 to 7.86±1.31%; 48.4±8.05 to 21.3±3.55(mg); 2.13±0.68 to 1.18±0.19% and 5.52±0.11 to 5.97±0.18%, individually. Additionally, the dampness, caffeine, polyphenol, lipid, protein, debris, ascorbic corrosive, corrosiveness and pH esteem from various matured leaves were found in oolong tea from 6.19±1.04 to 2.98±0.49%; 4.68±0.78 to 1.11±0.19%; 20.89±3.48 to 8.23±1.37%; 6.40±1.07 to 9.13±1.52%; 13.03±2.17 to 17.19±2.86%; 3.44±0.58 to 7.57±1.27% 6.44±1.08 to 0.98±0.17 (mg); 2.02±0.34to 1.02±0.17% and 5.53±0.11 to 5.97±0.20%, separately. In this manner, youthful tea leaves (for example 5 to 8 days tea leave..