Considerable evidence indicates that poor health has significant negative effects on labor force market activity. Nevertheless, because most of these analyses are based on cross-sectional data, their findings only indicate the relationship between poor health and work at a moment in time. This article uses a dynamic hazard model to examine how the onset of arthritis affects work behavior over the life cycle. The results indicate that the deterioration of health over time is the most significant determinant of why men with arthritis leave the labor force earlier than their otherwise healthy counterparts. These findings imply that the health-work relationship should be examined within the context of a life cycle framework to obtain a complete picture of the economic consequences of poor health.