OBJECTIVE: To determine the long-term natural history of patients with mild pulmonary valve stenosis METHODS: Throughout a 24-year evolutive period (1980 a 2004), 83 patients with pulmonary valve stenosis were evaluated, with 29 of them presenting a mild form of the defect. Of these 29, 13 patients had a long-term follow up. The mean age at the first and last follow-up visits was 34 months (1 month to 15 years) and 10.5 years (3 to 24 years), respectively. In addition to evolutive elements, those regarding clinical, electrocardiographic and echocardiographic aspects were also assessed. RESULTS: All patients remained assymptomatic throughout the study. Regarding the pulmonary valve pressure gradient, 5 (38.4%) presented a decrease, 3 (23%) remained unchanged, 4 (30.7%) presented elimination and 1 (7.6%) presented accentuation to a moderate degree of involvement. The mean initial and final gradient was 24.2 mmHg (15-30) and 13.6 mmHg (0-54), respectively. The initial gradients of the 4 patients who achieved spontaneous cure were 30, 19, 30 and 20 mmHg. The systolic murmur and right ventricular overload had a direct correlation to the gradient pressure degree, subdivided at each 10 mmHg. CONCLUSION: The spontaneous cure of the mild pulmonary valve stenosis is possible to achieve, similarly to other acyanogenic anomalies.