Objective To evaluate the psychometric and predictive performance of the Columbia-Suicide Severity Rating Scale (C-SSRS) in emergency department (ED) patients with suicidal ideation or attempts (SI/SA). Methods Participants (n = 1,376, mean age 36.8, 55% female, 76.8% white) completed the C-SSRS during the ED visit and were followed for one year. Reliability analyses, exploratory structural equation modeling, and prediction of future SA were explored. Results Reliability of the Suicidal Ideation subscale was adequate, but was poor for the Intensity of Ideation and Suicidal Behavior subscales. Three empirically derived factors characterized the C-SSRS. Only Factor 1 (Suicidal Ideation and Attempts) was a reliable predictor of subsequent SA, though odds ratios were small (ORs: 1.09–1.10, CI95%: 1.04, 1.15). The original C-SSRS Suicidal Ideation and Suicidal Behavior subscales and the C-SSRS ED screen predicted subsequent SA, again with small odds ratios (ORs: 1.07–1.19, CI95%: 1.01, 1.29). In participants without a SA history, no C-SSRS subscale predicted subsequent SA. History of any SA (OR: 1.98, CI95%: 1.43, 2.75) was the strongest predictor of subsequent SA. Conclusions The psychometric evidence for the C-SSRS was mixed. History of a prior SA, as measured by the C-SSRS, provided the most parsimonious and powerful assessment for predicting future SA.