Tanacetum chiliophyllum (Fisch. & Mey.) var. oligocephalum (D.C.) Sosn. collected in Turkey was subjected to phytochemical and biological evaluations in this study. Pure compounds were obtained from ethyl acetate extracts of the stems of the plant material. Structures of isolated compounds were determined using spectral methods. Seven known flavones, i.e., 5-hydroxy-3',4',6,7-tetramethoxyflavone, eupatilin (6-hydroxyluteolin-6,3',4'-trimethylether), cirsimaritin (scuttellarin-6,7-dimethylether), cirsilineol, 5 hydroxy-3',4',7-trimethoxy flavone, desmethoxy-centaureidin, and jaceosidin and one known triterpene, taraxasterol acetate, were identified from the ethyl acetate extracts. The first seven compounds, as well as the ethyl acetate and methanol extracts, were also investigated for their insecticidal, antimicrobial, and 1,1-diphenyl-2-picrylhydrazil radical (DPPH)-scavenging activities. The insecticidal contact toxicity of the extracts were evaluated on Sitophilus granarius. The ethyl acetate (81.8%) and methanol (88.4%) extracts of T. chiliophyllum var. oligocephalum showed high toxicity against this pest. Most promising antimicrobial activity was observed for ethyl acetate extracts of the stems against Bacillus cereus. This extract showed the same inhibition concentration (125 mu L/mg) with the positive control chloramphenicol. The ethyl acetate (91.9%) and methanol (93%) extracts of the stems showed significant DPPH-scavenging activity compared with the positive controls a-tocopherol (94.5%) and butylated hydroxytoluene (92.9%) at 10 mg/mL concentration. Among the isolated compounds, the highest DPPH-scavenging activity was observed for jaceosidin at 1 mg/mL concentration (81.5%).