Background. Counseling sedentary primary care patients can increase physical activity, but whether this approach will increase exercise and fitness in elderly adults with chronic diseases remains to be determined. Methods. After receiving individualized nurse counseling to begin a program of walking for health, 60- to 80-year-old primary care patients were randomized to one of three levels of telephone contacts over 10 months: (i) 20 nurse-initiated calls, (ii) 10 nurse-initiated calls plus 10 motivational calls programmed through an automated phone calling system, or (iii) no program-initiated phone contacts. Self-reported (diary) walking adherence was the primary outcome; other activity, social support, health quality of life, and measured walking performance, mobility, and body mass index and girths were also assessed during the initiation (months 1-6) and maintenance (months 7-10) phases of the trial. Results. Average adherence for the 181 participants to the goal of walking at least 20 minutes on 3 or more days per week was 44% for initiation and 42% for maintenance. Participants receiving the combination of nurse-initiated personal and automated phone calls walked significantly more frequently than those with no phone contacts. Fitness improved in all three groups; changes were generally correlated with self-reported walking. Having a companion was associated with more frequent walking. Perceived quality of physical and mental health did not change. Conclusions. Simple and relatively inexpensive nurse contacts can motivate elderly primary care patients to walk for exercise, and this activity is associated with measurable health benefits.