An outbreak of 81 cases of angiostrongyliasis cantonensis (AC) occurred in Beijing, China, during June through September 2006. Epidemiological characteristics, clinical signs and symptoms, laboratory tests, imaging, and treatment data from the 81 AC patients were collected and analyzed. All cases had a history of eating raw freshwater snails, and acquired Angiostrongylus cantonensis as a result. The incubation period ranged from 1 to 36 days. The main symptoms were fever, severe headache, neck stiffness, and skin paresthesia. A significant increase in eosinophilia occurred in the peripheral blood of 62 cases and in cerebrospinal fluid of 64 cases; 36 patients presented a linearly enhanced abnormal signal of the leptomeninges site during a cranial MRI examination, indicative of meningitis; 18 cases had a significant nodule shadow and spot flaky ground-glass shadow on chest computerized tomography. All patients were relieved of their illness with a 7-day treatment of albendazole.