Improvement in physical activity (PA) is an important benefit for patients undergoing CABG. It is suggested that women make less improvement than men. Of 568 patients (466 men and 102 women) undergoing an isolated primary CABG for stable angina (NYHA<4) pre- and 1-year postoperative PA was registered. The Corpus Christi Heart Project criteria are used for assessing PA. The different PA-levels are coded from 1, the worst, to 5, the best. Preoperatively, female patients were older, in a higher NYHA class, and PA level was significantly different and lower 2.30+/-1.01 vs. 2.89+/-1.03 (P=0.000). At follow-up, the mean PA increased significantly for women (2.7+/-1.02) and men (3.2+/-1.06) (P=0.000). Despite this broad increase, 20% of men and 10% of women had a decreased PA. Multiple logistic regression analysis identified a preoperative high PA-level, diabetes, vascular- and pulmonary disease (odds ratio 7.11, 2.6, 2.3, 2.69) as variables that contribute independently to a worse PA for men and only high preoperative PA level (odds ratio 11.0) for women. This study confirms that patients with a preoperative high level PA are unlikely to improve PA, but in men, diabetes, vascular- and pulmonary disease are also independent risk factors.