Assessment of the reliability, validity, and predictive power of a new measure, the Reasons for Living Inventory for Young Adults (RFL-YA) is described. A series of three studies was conducted at two Midwestern universities to develop initial items for this new measure, refine item selection, and demonstrate the psychometric properties of the RFL-YA. The theoretical differences between the RFL-YA and the College Student Reasons for Living Inventory (CS-RFL) are discussed. Although the two measures were not directly compared, it appears that the RFL-YA has greater specificity for exploring aspects of the protective construct and may be more parsimonious than the CS-RFL. Principal-axis factor analysis yielded a five-factor solution for the RFL-YA accounting for 61.5% of the variance. This five-factor oblique model was confirmed in the final phase of investigation. Alpha estimates for the five subscales ranged from .89 to .94. Concurrent, convergent-discriminant, and criterion validity also were demonstrated. The importance of assessing protective factors in addition to negative risk factors for suicidality is discussed. Directions for future research with the RFL-YA also are discussed. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 339–357, 2002.