Background We have developed the Suicide Crisis Inventory (SCI) to evaluate the intensity of the Suicidal Crisis Syndrome, an acute state hypothesized to precede suicide attempt. The psychometric properties of the SCI, including predictive validity for suicidal behavior (SB), were assessed. Methods Adult psychiatric patients (n = 201) hospitalized for high suicide risk were assessed. Logistic regression models assessed the SCI's predictive validity for SB in the 4–8 weeks following hospital discharge and its incremental predictive validity over traditional risk factors (n = 137, 64% f/u rate). Internal structure, reliability, convergent and discriminant validity, and state versus trait properties were also assessed. Results The SCI had excellent internal consistency (Cronbach's α 0.970). The SCI total score at discharge predicted short‐term SB with 64% sensitivity 88% specificity (OR = 13, P = .003) at its optimal cut score. In a test of its incremental predictive validity, SCI total score at discharge improved prediction of SB over traditional risk factors (Chi‐squared 5.597, P = .024, model P = .001), with AOR 2.02 (P = .030). The SCI admission versus discharge test–retest reliability and score distributions showed it to be an acute state measure. Conclusion The SCI was predictive of future SB in high‐risk psychiatric inpatients during the crucial weeks following their hospital discharge. Further validation in diverse patient populations is needed.