Three cheetahs (Acinonyx jubatus) had a clinical history of chronic spiral bacteria-associated gastritis and three cheetahs had no clinical history of gastritis. Gastric biopsies were obtained from all six cheetahs prior to treatment for gastritis and 3 wk and 1 yr posttreatment. The cheetahs were treated with tetracycline hydrochloride 500 mg p.o. q.i.d., metronidazole 250 mg p.o. q.i.d., and bismuth subsalicylate 300 mg p.o. q.i.d. Each drug was administered concurrently for 7 days. Following this treatment, each cheetah was maintained on 300 mg bismuth subsalicylate p.o. s.i.d. for 1 yr. The three cheetahs with a history of gastritis were culture positive for Helicobacter acinonyx and remained positive during the entire study. The three cheetahs with no clinical history of gastritis were culture negative for H. acinonyx, but gastric biopsies revealed Gastrospirillum-like bacteria (tentatively named Helicobacter heilmannii) pretreatment. Gastric biopsies were negative for H. heilmannii on subsequent examinations. Although the treatment did not eradicate H. acinonyx, it did provide symptomatic relief from the vomiting, anorexia, and weight loss associated with clinical gastritis. The use of endoscopically guided gastric mucosal biopsies for urease testing and histopathologic examination of Warthin-Starry-stained sections is a sensitive and specific method of diagnosing spiral bacteria-associated gastritis. Treatment of spiral bacteria-associated gastritis in cheetahs should include the rational use of antibiotics (tetracycline or amoxicillin and metronidazole), bismuth compounds, and omeprazole and evaluation of husbandry methods to reduce stress.