Randomized clinical trial carried out to investigate the effectiveness of the cognitive-behavioral approach and nicotine replacement therapy with nicotine patches for smoking cessation. Participated 1,199 adults, volunteers, in Rio de Janeiro, Brazil, randomly assigned to 10 different groups: intensive brief counseling group (GB), with 1 or 2 sessions (G1-G2), and with 3 or 4 sessions (G3-G4), with/without nicotine replacement therapy (NRT). Abstinence proportions were estimated during 12 months. These proportions among participants not assigned to NRT were 20% (GB), 17% (G1-G2), and 23% (G3-G4); and among assigned NRT groups were 30% (GBA), 34% (G1A-G2A), and 33% (G3A-G4A). After multiple adjustments, the abstinence proportions ratios seemed to follow a "dose-response" pattern: compared to GB, the ratios were 0.85 (G1-G2), 1.13 (G3-G4), 1.51 (GBA), 1.66 (G1A-G2A), and 1.75 (G3A-G4A). The results suggest that use of NRT increases the abstinence proportion for cessation. The "dose-response" pattern suggests that cognitive-behavioral could be the reasonable option in the smoking cessation therapy.