Clients' motivation to engage in health promotion, health maintenance, and risk-reduction activities has been of long-standing concern to public health nurses. While health practices are often attributed to motivation, no measurement of this construct has existed to assist us in either assessing or developing interventions relative to this characteristic. This study reports additional psychometric data on a new multidimensional measurement of motivation and examines selected predictors of the measurement The test-retest correlation over a two-week period for the total instrument was 0.86. Age, sex, and educational level accounted for 18 percent of variance in the total construct Age, sex, educational level, and income differentially explained 15,15,9, and 11 percent of the respective ante in the construct's four separate dimensions-judgment, behavior, competency, and intemaYextemal cue responsiveness. The results provided evidence of the stability of the health selfdeterminism index (HSDI) and supported the significant contributions of four sododemographic tmiables in predicting total and subscale scores. The HSDI may prove to be useful to public health nurses in dent assessment and as a guide for developing specific intewentions at both the individual and aggregate levels.