The Belgian Heart Disease Prevention Project is a controlled, multifactorial prevention trial involving 19,390 males aged 40-59 years employed by 30 Belgian industries. These industries were paired and randomized into a control or intervention unit. In each intervention factory, the subjects from the two highest deciles of a coronary risk-score distribution curve were given individual advice twice a year. A health education campaign was also organized in each intervention factory. In the control group, 10% of randomly chosen subjects had the same baseline examination as the whole of the intervention group. After 2 years, high-risk subjects and random samples of the control and intervention group were compared regarding the coronary risk profile by means of a multiple logistic function (MLF). In the intervention high-risk group, the MLF showed a decrease of 20%, and in the control group there was an increment of 12.5% (p less than 0.001). Comparing the random samples an increment of 25% was found in the control group vs a drop of 2.26 in the intervention group (p less than 0.001). The coronary risk profile can be altered in a middle-aged male working population through mass media health education supplemented by face-to-face counseling in high-risk subjects.