The relationship between body height, weight and body mass index and mammographic patterns was examined among 3,208 Norwegian women, aged 40-56 years, participating in the Third Tromso study. Standardized measurements of height and weight were recorded. Epidemiologic data were obtained through questionnaires. Mammograms were categorized into S groups based on anatomic- mammographic correlations. For analysis, patterns I-III were combined into a low-risk group and patterns IV and V into a high-risk group. Odd ratios (ORs), adjusted for menopausal status, age, parity, age at first birth, age at menarche and anthropometric measures, with 95% confidence intervals (CIs), were calculated. Body height was associated positively with high-risk patterns, while weight and body mass index were associated inversely with high-risk patterns. Women in the highest tertile of height were twice as likely (OR = 2.0, 95% CI 1.6-2.6) to have high-risk patterns compared with those in the lowest tertile, and women in the highest tertile of weight were 70% less likely (OR = 0.3, 95% CI 0.2-0.4) to have high-risk patterns compared with those in the lowest tertile. Associations with body mass index were similar to those with weight. All associations were present when stratified by menopausal status. Among post-menopausal women, the inverse associations between body weight and body mass index and high-risk patterns decreased with increasing number of years since menopause. Our results indicate that body height and weight are independently associated with the mammographic pattern among peri-menopausal women. We suggest that body height and weight are related to mammographic patterns through different mechanisms.