Background: Evidence shows screening youth for suicide risk in pediatric care settings is a critical component for prevention. Nonetheless, there is some ambiguity about which assessment tools are most appropriate for detecting risk. The current study evaluated the performance of two widely used suicide risk screening instruments, the Patient Health Questionnaire (PHQ-9) item 9 and the Ask Suicide-Screening Questions (ASQ). While the ASQ is suicide-risk specific, the PHQ-9 focuses on depression severity with a final question assessing recent thoughts of death or self-harm. Methods: Data were obtained from the Emergency Department Study for Teens at Risk for Suicide (ED-STARS), a multisite longitudinal cohort study that recruited youth aged-12-17 years from 13 U.S. pediatric emergency departments between 2015-2016. Youth completed assessments at baseline and at 3-month follow-up to determine the occurrence of suicide attempts. Area under the curve (AUC), sensitivity, and specificity values for predicting future suicide attempts in youth were compared between the ASQ and the PHQ-9 item 9 both overall and in the following subgroups: sex at birth, race, ethnicity, sexual/gender minority status, and presenting chief complaint (psychiatric vs. medical). Acceptable values of sensitivity and specificity were set at > 80% and >50%, respectively, per Runeson et al. 2017 (PMID: 28723978). Results: 2075 study participants were mostly female (63%), White (54%), and non-Hispanic (67%) with a mean [SD] age of 15.1[1.6] years at enrollment. The ASQ demonstrated higher sensitivity compared to the PHQ-9 item 9 in predicting suicide attempt overall (0.961 [95% CI, 0.953-0.970]) vs (0.748 [95% CI, 0.729-0.766]) and across all subgroups. The ASQ performed significantly better than the PHQ-9 item 9 among youth presenting with medical chief complaints (0.867 [95% CI, 0.850-0.883]) vs (0.467 [95% CI, 0.442-0.491]). Specificity of the PHQ-9 item 9 was higher overall (0.729 [95% CI, 0.709-0.748]) vs (0.539 [95% CI, 0.518-0.561]) and across all subgroups The AUC findings were similar for both instruments in the overall comparison (0.750 [95% CI, 0.731-0.769]) vs (0.738 [95% CI, 0.719-0.757]), and all subgroup analyses. Discussion: Findings show the ASQ has higher sensitivity than PHQ-9 item 9, suggesting improved capabilities to identify youth at risk for suicide, offset by lower specificity with the potential for more “false positive” designations. The sensitivity of the ASQ was > 80% overall and across all subgroups, indicating acceptable diagnostic accuracy. In contrast, the PHQ-9 item 9 did not achieve > 80% sensitivity overall and in most subgroup analyses. Using a suicide-specific screening tool may be more effective than depression screening tools in identifying youth suicide risk.