Abstract The fruit of the Osage orange tree (Maclura pomifera (Raf.) Schnied.) was extracted by several methods: solid phase microextraction (SPME) volatile trapping of the headspace, solvent extraction with hexane, soxhlet extraction with hexane or methylene chloride and steam distillation. The isolates from each technique were subjected to GC/MS to compare extract components. Ripe and unripe fruits were compared using SPME. Several compounds of terpenoid structure, mostly sesquiterpenoids, were determined as present in the isolates. Among these were elemol/hedycaryol, α-copaene, α-cubebene, δ-cadinene, β-elemene, β-caryophyllene, α-ylangene/valencene, (Z,E)-farnesol and the green volatile hexyl hexanoate. The behavioral response of German cockroaches [Blattella germanica (L.)] to the oil and extracts was examined in a choice arena, and the extracts were found to be repellent. Individual compounds, including the isoflavones osajin and pomiferin, were purchased or isolated and tested directly, and several were found to be repellent to the cockroaches. Key Word Index: Madura pomifera MoraceaeOsage orangeessential oil compositionextract compositionheadspace analysiselemol/hedycaryolα-cubebeneγ-cadineneβ-elemene(Z,E)-farnesolhexyl hexanoateosajinpomiferin Blattella germanica cockroach repellency