Aim: The present study deals with the complete morphological, microscopic, physicochemical & phytochemical screening of whole plant of Parthenium hysterophorus.

Materials and Methods: Thin transverse sections of fresh root, stem & leaf were taken for the morphological & microscopical studies. Dried whole plant powder was used for physicochemical analysis. For preliminary phytochemical study aqueous extractives of plant were used.

Results: Detailed Pharmacognostic study of leaf, stem and root indicated the plant was dicotyledons type. In proximate analysis of plant, the value of loss on drying was found to be 4.05±0.5% w/v. The total ash, acid insoluble ash & water soluble ash were found to be 14.28±0.72% w/w, 4.76±0.24% w/w & 9.52±0.48% w/v respectively. The alcohol soluble extractive, water soluble extractive values were found to be 32±1.0% & 16±0.95% w/v respectively. Phytochemical screening of aqueous extract of Parthenium hysterophorus showed the presence of triterpenoids, alkaloids, flavonoids, steroids and glycosides.