Acacia catechu (L.) willd, commonly known as Khadira, is widely used in Ayurveda for the treatment of diseases. A detailed investigation of fresh and powder of heartwood of A. catechu was carried out. The diagnostic characters of heartwood of this plant includes tylosis formation, fibers with prism, fibers with scleroids, fragment of border pitted vessels, starch grains with hylem along with yellowish dark brown colouring matter, lignified fibers and fibers passing through medullary rays. Physicochemical studies revealed loss on drying (7.15%), total ash (2.8%), acid insoluble ash (0.04%), alcohol-soluble extractive (15.78%), water-soluble extractive (12.00%) and tannin content in raw drug is (08.28%). Quantitative microscopy includes tyloses, parenchyma length and circumferences. Preliminary analysis of various functional groups revealed the presence of alkaloids, tannin, saponins, carbohydrate, starch, steroid and proteins. The information generated by this particular study will provide relevant pharmacognostical and physicochemical data needed for proper identification and authentication of heartwood of this particular species. Key words: Acacia catechu, heart wood, pharmacognosy, tylosis