The 2-month results of a study designed to compare the effectiveness of three methods to encourage giving up smoking in primary health care are reported: individualized medical counseling (minimal intervention), counseling plus follow-up option by the nurse, and medical counseling plus nicotine chewing gum. Overall 425 smokers between 15 and 65 years of age were included in the study. In 349 of them (82%), short term follow-up was carried out by phone interview. The proportion who declared to have given up smoking, after adjustment for the estimated validity of the phone report of smoking status, was 10, 9%, 10.8% and 11.1%, respectively, without significant differences between the three groups. In the logistic regression analysis, only the existence of concomitant disease and the anticipated difficulty in giving up smoking appeared as predictive variables of abstention. The implications of the results for the strategies to control smoking are discussed.