Greenhouse experiments simulated field treatments with Premise® 75 WP imidacloprid insecticide at the highest recommended labeled rate (0.10% AI) for prevention and control of subterranean termites around and within structures. Persistence of imidacloprid was examined in treated sandy loam soil with and without vegetation. Samples from soil substrates and leachates collected 1, 3, 6, 9, and 12 months after treatment during a 1-year post-treatment period were analyzed by high-performance liquid chromatography. The mean concentrations of imidacloprid in the treated soil and leachate immediately after application were 842.6 ± 9.2 µg per gram and 941.5 µl per liter, respectively. Recovery of imidacloprid utilizing high-performance liquid chromatography was 84.2 ± 9.2 and 94.5 ± 10.6%, respectively. No imidacloprid was found in soil or leachate 6 months after treatment. The results indicated that imidacloprid was soluble and leached from the treated soil.