Nonsuicidal self-injury (NSSI) is a growing public health problem among adolescents and young adults. The Inventory of Statements About Self-Injury (ISAS) is a self-report measure designed to assess NSSI behaviors and functions. The current study examines the one-year test-retest reliability of the ISAS in a sample of young adult self-injurers. Results indicate that the ISAS behavioral and functional scales demonstrate good stability over one year. For the behavioral scales, test-retest correlations ranged from 0.52 (biting) to 0.83 (burning), with a median of 0.68. For the functional scales, test-retest correlations were 0.60 for the superordinate intrapersonal functions scale and 0.82 for the superordinate interpersonal functions scale. Regarding individual functions, test-retest correlations ranged from .35 (affect regulation) to 0.89 (peer bonding), with a median of 0.59. Findings suggest the ISAS has good test-retest reliability and contributes to the growing literature on the psychometric properties of the ISAS. (Contains 2 tables.)