Using ultra performance liquid chromatography, voriconazole concentrations in plasma samples from red-eared slider turtles (Trachemys scripta elegans) were quantified after single subcutaneous (SC) injections of 5, 10, and 20 mg/kg, and after twice-daily SC injections for 7 days at a dose of 10 mg/kg. Voriconazole was rapidly absorbed after SC injection. Plasma concentrations obtained after the last of multiple doses (10 mg/kg SC q 12 h for 7 days) revealed a mean (SD) observed time of maximum concentration = 1.29 (1.28) h; observed maximum concentration = 7.58 (5.39) μg/ml; and time above 1.0 μg/ml = 7.43 (2.16) h. Doses of 10 mg/kg administered twice daily for 7 days resulted in trough concentrations that were subtherapeutic based on current recommendations for clinical efficacy of antifungal therapy in humans. Clinical abnormalities were seen in several turtles during and after the study, but these effects could not be definitively attributed to voriconazole administration.