The whole plant of Catharanthus pusillus of family Apocynaceae was subjected to isolation and identification of chemical constituents. The extract was purified and isolated by column chromatography and thin layer chromatography (TLC). The isolated compound was then subjected to UV spectrum, FTIR for identification of functional groups and 1HNMR and 13C-NMR for identification of protons and carbon atoms. ESI-MS was done to identify the molecular weight of the isolated compound. From the interpretation of the spectral data, the isolated compound was found to be 3-β acetyl oleanolic acid.