Fasting plasma lipid and lipoprotein concentrations were determined in 25 men and 25 women (mean ages 42 and 39 yr respectively) whose exclusive mode of regular exercise was tennis play. When compared to a sedentary group matched for age, sex, and education, the tennis players exhibited similar plasma total cholesterol and LDL-cholesterol concentrations and significantly lower triglyceride and VLDL-cholesterol concentrations. Plasma HDL-cholesterol was significantly higher in the tennis players (57.8 +/- 13.9 versus 46.2 +/- 12.0 mg/100 ml in the men and 73.9 +/- 12.3 versus 61.7 +/- 13.3 mg/100 ml in the women). When we simultaneously controlled for age, relative weight, cigarette smoking, alcohol intake, and oral contraceptive use (in females), the significance of the difference in plasma HDL-cholesterol as well as triglyceride and VLDL-cholesterol concentrations was unaffected in the males but substantially reduced in the females. It is concluded that frequent tennis playing is associated with increased plasma HDL-cholesterol concentrations and that this relationship is independent of other factors known to alter plasma HDL-cholesterol concentration.