This study evaluated the caries risk profile of patients with severe intellectual disabilities (IDs) who received dental treatment under general anesthesia. One hundred and two patients with ID [ID group, mean age (SD); 23.8(9.3)] and 100 healthy patients without ID [NID group, mean age (SD); 23.19(3.3)] were included. Medication, disability type, oral hygiene maintenance, and cooperation of the patients were investigated. Dietary habits, plaque index, mutans streptococci counts, fluoride availability, and salivary buffering were scored and analyzed using the Cariogram. The mean chance of avoiding caries (SD) was 28.1(20.4) in the ID group and 54.7(18.4) in the NID group. The ID group had significantly higher numbers of decayed and missing teeth, but fewer filled teeth than the NID group (p < .05). Significant disparities existed in the distributions of all caries-related factors except for mutans streptococci counts between the two groups (p < .05). The low chance to avoid future caries in ID patients was closely associated with insufficient oral hygiene maintenance (p < .05). Fluoride availability was strongly associated with the chance of avoiding caries in the ID group. Dental patients with severe ID exhibited a higher risk of developing caries than normal patients. Among several caries-related factors, insufficient oral hygiene maintenance and low fluoride availability most contributed to the high risk.