The genus Conyza (Asteraceae) comprises about 50 species and found in the tropical and warm regions. Extracts from Conyza species have numerous pharmacological applications. The aim of this study was review the chemical composition and biological activity of Conyza species. Extracts from the plants have antimicrobial, antioxidant, cytotoxic, anti-inflammatory, antiplasmodial, analgesic, antiviral, allelopathic and insecticidal activities. The constituents of essential oils from Conyza species include limonene and β-farnesene, were caryophyllene, spathulenol, β-ocimene, lachnophyllum ester, matricaria ester, germacrene D, α-bergamotene, caryophyllene oxide, pinene, bicyclogermacrene, curcumene, cadinene , sesquiphellandrene, camphene, 2,6,7,7a-tetrahydro-1,5-dimethyl-1H-indene-3-carboxaldehyde, 2-heptylacetate, allo-aromadendrene, bisabolene oxide, carvacrol, cis-sabinol, epi-bicyclosesquiphellandrene, humulene, isoeugenol, isospathulenol, mentha-1,3,8-triene, myrcene, neophytadiene, perillaldehyde, phytol, pinocarveol, pulegone, Sabinene, terpinolene, zingiberene and β-copaen-4-α-ol. The findings indicate that only a few species have been studied including C. bonariencis, C. canadensis, C. sumatrensis and C. floribunda. Further investigations especially on the neglected species is necessary