1756 The purpose of this study was twofold: 1) To characterize the impact of general health improvement program promotions on the readiness to change (RTC) stage for physical activity of the HMO membership, and 2) to identify, based on RTC staging, where the most potential for physical activity promotion resides. A random sample of HMO members stratified by chronic condition(N=8,000) was surveyed by mail as an observational cohort in 1995 and 1996. RTC was collected using the Prochaska, et al., five-stage model that outlines the following stages: Precontemplation (P), contemplation (C), preparation(PR), action (A) and maintenance (M). Movement across stages over the course of one year was quantified via construction of a 5x5 RTC table that presented the proportion of subjects by RTC stage in 1995 and 1996. Progress was attributed to the proportion of members who moved from a stage associated with inactivity (P/C/PR) to an active stage (A/M). Relapse was attributed to the proportion of members who moved from A/M back into P/C/PR. Relapse from A and M back into P/C/PR was considered in order to identify potential for intervention efforts. Demographics of the subject sample with complete data for 1995 and 1996 (N=5102) include (mean±SD): Age=61±12 yrs, weight=78.9±17.8 kg, BMI=27.4±5.2 kg/m2, and 53% female. Results indicate that 52.9% of the sample had not changed RTC stage Progress from P/C/PR into A/M occurred in 33.0% of the population. Relapse from A/M back into P/C/PR occurred in 20.9% of the population (mean net change = 12.1% progress). Progress from P/C/PR into A and M was 14.6% and 18.5%, respectively. Relapse from A and M into P/C/PR was 34.0% and 16.7%, respectively. These data suggest that great potential exists for increasing physical activity prevalence by effectively preventing relapse for those in A and M.