Serum lipoprotein(a) [Lp(a)] levels were measured before and after a 12-wk program of moderate-intensity endurance training. The training program consisted of walking and/or jogging, at least three sessions·wk-1 of at least 30 min duration, at an intensity producing 60-85% HRmax reserve. Twenty-eight previously sedentary middle-aged Caucasian males matched for age, body mass, and body mass index(BMI) were randomly allocated to either an exercise (N = 17, mean age ± SEM = 51.57 ± 1.25 yr) or a control (N = 11, mean age ± SEM = 50.0 ± 1.15 yr) group. Pre- and post-training median Lp(a) levels, measured by immunoturbidimetric analysis, were not significantly different in either the exercise (pre 13.0, post 15.0 mg·dl-1) or the control subjects (pre 14.0, post 12.0 mg·dl-1)(P > 0.05). Kendall Rank correlation analysis revealed no significant relationship between the level of Lp(a) and any other variable in either group before or after training. In the exercisers, a significant increase (P < 0.05) was recorded in the estimated mean ˙VO2max (pre 33.39 ± 1.70, post 37.7 ± 1.75 ml·kg-1·min-1). These data indicate that the level of Lp(a) was not influenced by a 12-wk program of moderate-intensity endurance training, and are consistent with previous reports suggesting that Lp(a) level is not altered by lifestyle factors.