In laboratory choice tests with either filter paper treatment or sand treatment, naphthalene and 10 derivatives were evaluated for their effects on the behavior of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). After 24-h exposure, workers avoided 50µg/cm²-treated filter paper with 1′- and 2′-acetonaphthone. By day 8, feeding activity on filter paper treated with 1- and 2-methoxynaphthalene, 1′- and 2′-acetonaphthone were significantly reduced compared with the controls. Naphthalene and six other derivatives were not effective at 50µg/cm²-treated filter paper. After 12-d exposure, tunnels constructed in sand treated with 1- and 2-methoxynaphthalene (0–3 cm²), 1′- and 2′-acetonaphthone (2–9 cm²), 2-naphthalene methanol (14–19 cm²), or 2-isopropylnaphthalene (16–19 cm²) at the rate of 100 mg/kg sand were significantly less than the controls (34 cm²). Consumption on filter paper placed on sand treated with 1- and 2-methoxynaphthalene and 1′- and 2′-acetonaphthone was significantly reduced (0–7 mg) compared with the controls (33–54 mg). 1-Methoxynaphthalene was the only treatment that caused significantly less feeding activity in the untreated sand chamber (0–6 mg) compared with the control (63–128 mg).