BACKGROUND: Although many foods and nutrients are associated with lung function or symptoms of chronic obstructive pulmonary disease (COPD), the relation between overall diet and newly diagnosed COPD is not known. OBJECTIVE: We assessed the relation between dietary patterns and newly diagnosed COPD in women. DESIGN: Data were collected from a large prospective cohort of US women (Nurses' Health Study). Between 1984 and 2000, 754 self-reported confirmed cases of newly diagnosed COPD were identified among 72 043 women. With the use of principal component analysis, 2 dietary patterns were identified: a prudent pattern (fruit, vegetables, fish, whole-grain products) and a Western pattern (refined grains, cured and red meats, desserts, French fries). Patterns were categorized into quintiles, and the risk of COPD was compared between quintiles (lowest as reference) with the use of Cox proportional hazard models. RESULTS: After adjustments for 14 potential confounders, the prudent pattern was negatively associated with risk of newly diagnosed COPD [relative risk (RR) for highest compared with lowest quintile: 0.75; 95% CI: 0.58, 0.98; P for trend = 0.02] whereas the Western pattern was positively associated with risk of COPD (RR for highest compared with lowest quintile: 1.31; 95% CI: 0.94, 1.82; P for trend = 0.02). In contrast with findings for COPD, dietary patterns were not associated with the risk of adult-onset asthma. CONCLUSION: In women, a negative association was found between a diet rich in fruit, vegetables, and fish and the risk of COPD, whereas a positive association was found between a diet rich in refined grains, cured and red meats, desserts, and French fries and the risk of COPD.