Adolescent engagement in risk-taking and life-compromising behaviors has become a public health concern. This paper describes the development of three alternate forms of a new scale to measure suicidal and risk-taking behavior, the Life Attitudes Schedule (LAS). The LAS, which was developed and piloted on 1,539 high-school students and young adults, is based on a broad conceptualization of suicidal behavior. It is unique because it is derived from a broad theoretical perspective. The LAS measures four different content categories: (1) death-related; (2) health-related; (3) injury-related; and (4) self-related. Each content category includes an equal number of items designed to assess actions, thoughts, and feelings. The LAS was designed to measure a bipolar continuum of behavior; consequently, an equal number of positive (life-enhancing) and negative (life-compromising) items are included. Three approaches were used to evaluate the validity of the LAS: correlational analyses, construct and criterion validity analyses, and structural equation modeling to test several theoretical models underlying the LAS. The results indicate both that this instrument has excellent reliability and validity properties and provides validation of the construct of life-compromising and life-enhancing behaviors. Six tables present sample items and statistical summaries. Contains 40 references. (Author/RJM)