Plants are sources of many natural active compounds used to prevent several diseases. The various parts of plants like leaf, stem, flower and root are rich of these bioactive compounds. From ancient times these natural compounds have been using for treatment and prevention of diseases. Cosmos bipinnatus is an herbaceous, medicinal plant. The present study was aimed with the objective to antioxidant, antimicrobial and phytochemical screening, total phenolic and total flavonoid content of different solvent extracts of different parts of Cosmos bipinnatus. Flavonoids were abundantly found in the leaves and the root of Cosmos bipinnatus. Steroids were absent only in the leaves and flowers of Cosmos bipinnatus while terpenoids were completely absent in the flowers of the plant. Alkaloids were absent in the leaves extracted from all the three solvents and root sample extracted using ethyl acetate and stem sample extracted using ethanol. Proteins are absent in all the parts of the plant extracted using all the three solvents namely ethanol, ethyl acetate and hexane. Tannins are absent in the entirely in the flower in addition to the stem sample taken using the solvent hexane. Saponins are present all the parts like leaf, stem and flower but are not found in the root extract of the plant. The total phenolic and flavonoid contents of the extracts were calculated by using the standard gallic acid and quercetin graphs to find out the concentration. The total phenolic content is high for the plant sample stem that is extracted by using hexane as the solvent the value is 790µg/mg. The total flavonoid content is high for the plant sample stem that is extracted by using hexane as the solvent the value is 150µg/mg. The antioxidant activity was also found out by using various assays like FRAP and DPPH where the percentage of inhibition was found out. The highest percentage of inhibition for leaf was found out to be at 120µg/ml with the solvent hexane that is 88.86%. The highest percentage of inhibition for stem was found out to be at 60mg/ml using ethanol that is 89.92%. The highest percentage of inhibition for flower was found out to be at 60mg/ml by ethyl acetate that is 91.42%. The highest percentage of inhibition for root was found out to be at 60mg/ml that is 97%. From the FRAP results it is evident that the antioxidant activity is highest for the root sample.