The results of 66 training studies involving the measurement of human blood lipid and lipoprotein changes over time, conducted over the last 26 yr, and representing 2925 subjects (2086 experimental and 839 control) were collected and statistically aggregated using the meta-analysis technique. Across all types of subjects, treatments, sources, and research designs, the average exercising subject was found to have a reduction in total cholesterol of 10 mg X dl-1 (P les than 0.01), total triglyceride decreased by 15.8 mg X dl-1 (P less than 0.01), DHL-C increased by 1.2 mg X dl-1 (NS), LDL-C decreased by 5.1 mg X dl-1 (P less than 0.05), and total/HDL-C ratio showed a large decrease of 0.48 (P less than 0.01). None of the changes for the control groups were significant. Initial levels of total cholesterol, total triglyceride, HDL-C, and total/HDL-C ratio were strongly correlated with their respective changes as a result of training, regardless of the data partitioning. Higher initial levels of total cholesterol, total triglyceride, and total/HDL-C ratio resulted in greater decreases post-exercise (r = 0.48, 0.76, and 0.75, respectively; P less than 0.01), and lower initial levels of HDL-C resulted in greater post-exercise increases (r = 0.50; P less than 0.01). Overall, physical training seemed to produce beneficial changes in blood lipids and lipoproteins. However, researchers must be careful when examining the relationship between physical training and serum lipids and lipoproteins because initial levels, age, length of training, intensity, VO2max, body weight, and percent body fat have been shown in this meta-analysis to interact with exercise and serum lipid and lipoprotein changes.