Data from 64 adolescent inpatients admitted for serious suicidal ideation, 50 adolescent inpatients admitted following a suicide attempt, and 56 randomly selected high school control participants were used to evaluate the sensitivity, specificity, positive predictive value, and negative predictive value of the Suicidal Ideation Questionnaire (SIQ) and the Reynolds Adolescent Depression Scale-2nd Edition (RADS-2). The purpose of the study was to provide information necessary for selecting assessment tools to use in large-scale screenings of high school students for suicide risk. The hypothesis that a combination of mean scores on the two measures and critical item scores would provide the best clinical utility was partially supported. The SIQ was found to be very useful in discriminating between the study groups, whereas the RADS-2 did not perform as expected. The fewest false negatives would result from relying on RADS-2 scale scores greater than or equal to 63 and SIQ scale scores greater than or equal to 14. However, the parsimonious and hence most cost-effective approach would be to rely on SIQ scale scores greater than or equal to 14 in combination with SIQ critical Items 2, 3, and 4 for screening purposes. (Contains 8 tables.)