Objective: This study reports the reliability and validity of the 13-item Stanford Presenteeism Scale (SPS). The SPS differs from similar scales by focusing on knowledge-based and production-based workers. Methods: Data were obtained from administrative and medical claims databases and from a survey that incorporated the SPS, SF-36, and the Work Limitations Questionnaire. Results: Sixty-three percent (7797) of employees responded. Cronbach's alpha (0.83) indicates adequate reliability. Factor analysis identified two underlying factors, "completing work" and "avoiding distraction." Knowledge-based workers load on "completing work" (α = 0.97), whereas production-based workers load on "avoiding distraction" (α = 0.98). There were significant and positive relationships between the SPS, SF-36, and Work Limitations Questionnaire. Conclusions: The SPS demonstrates a high degree of reliability and validity and may be ideal for employers who seek a single scale to measure health-related productivity in a diverse employee population.