To evaluate the clinical efficacy and safety of voriconazole for the treatment of aspergillosis in falcons, 20 falcons with aspergillosis admitted to the Dubai Falcon Hospital from August 2003 to May 2006 were treated with voriconazole. These falcons included 6 gyrfalcons (Falco rusticolus), 10 gyrfalcon hybrids, 1 lanner (Falco biarmicus), 1 saker (Falco cherrug), and 2 peregrine falcons (Falco peregrinus). Clinical signs were weight loss, inappetence, dyspnea, inspiratory stridor, tachypnea, and biliverdinuria. Aspergillosis was diagnosed from clinical signs, hematologic results, radiographic abnormalities, endoscopic examination of the lower respiratory tract, cytologic examination of biopsy samples from air sacs, and fungal cultures. Birds treated with voriconazole administered by crop gavage were divided into 2 groups: in group 1, birds were treated with 12.5 mg/kg q12 h for 3 days (loading dose), then q24h for an additional 18 to 87 days; in group 2, birds were treated with 12.5 mg/kg q12h for the full period of 44 to 100 days. Treatment with voriconazole resulted in a successful clinical response in most cases, an acceptable survival rate, and few adverse effects. Complete clinical resolution occurred in 14 birds (70%), a partial response in 5 birds (25%), and 1 bird (5%) died during treatment. From these results, voriconazole appeared to be effective and safe for the treatment of aspergillosis in some species of falcons.