A total of 7085 falcons were presented for examination during a 56-month period from September 1998 to May 2003 at the Falcon Specialist Hospital and Research Institute of the Fahad bin Sultan Falcon Center, Riyadh, Kingdom of Saudi Arabia. We diagnosed infection with Trichomonas gallinae in 393 of 7085 (5.5%) falcons examined, including 346 (88%) saker falcons (Falco cherrug), 30 (8%) peregrine falcons (Falco peregrinus), 8 (2%) lanner falcons (Falco biarmicus), 5 (1%) gyr falcons (Falco rusticolus), and 4 (1%) gyr hybrid falcons. Trichomoniasis appears to be directly linked to the traditional Arab falconry practices of training falcons using live domestic pigeons (Columba livia) and feeding them freshly killed domestic pigeons and doves (Streptopelia species). Anatomical sites affected included the oropharynx (63% of birds), crop (31%), esophagus (10%), nasal cavity (4%), infraorbital sinus (5%), and syrinx (2%); more than 1 anatomical site was affected in some birds. The less common, atypical presentations of trichomoniasis could present a diagnostic challenge to the attending clinician. The diagnosis of trichomoniasis was confirmed by observing T gallinae on wet-mount preparations of samples collected from the lesions using moistened microbiology swabs. The primary therapeutic protocol for clinical trichomoniasis included metronidazole at a dosage of 100 mg/kg PO q24h for 3 days and supportive care. At 3–7 days after completing the course of metronidazole, we surgically debrided the trichomonal lesions as necessary, depending on the severity and location of the infection. Resolution of T gallinae infections was satisfactory in most cases. Four falcons died secondary to the infection.