Background: There are few cross-sectional population-based studies on obesity in Hungary. Aim of this study was to characterize the prevalence, associated diseases and metabolic laboratory parameters for obesity in men and women in Budapest, Hungary. Methods: A random sample of 641 persons (307 males and 334 females) aged 50 years and over were recruited from a population register in Budapest. Subjects were interviewed, had height and weight measured in standard fashion. Those who were obese (BMI > 30.0 kg/m(2)) were matched individually with non-obese subjects. Altogether 101 pairs (48 women and 53 men pairs) were taking part and these subjects had blood taken for amount of serum glucose, lipids and uric acid. Results: The mean age of men and women was 65.0 (SD = 9.1) years and 64.6 (SD = 8.9) years, respectively. The prevalence of obesity was 18.1% in men and 15.4% in women (p < 0.05). In both sexes the mean body mass index was higher at age of 50-64 years than at older ages [in 27.2 (SD = 3.7) kg/m(2) vs. 26.7 (SD = 3.3) kg/m2, p = 0.286 and in women 26.7 (SD = 4.2) kg/m(2) vs. 25.4 (SD = 4.0) kg/m(2), p = 0.005]. Body mass index was higher in men than in women at all ages. In the case-control study the mean age of obese and non-obese individuals were 63.1 (SD = 7.8) years and 63.2 (SD = 7.9) years, respectively. Obesity was significantly associated with a history of diabetes mellitus (18 vs. 7%, p < 0.05) and hypertension (48 vs. 28%, p < 0.05). Compared to the non- obese, those who were obese had a higher level of serum uric acid (311 +/- 102 vs. 280 +/- 96 mu mol/l, p < 0.05) and triglyceride (2.67 +/- 1.95 vs. 1.86 +/- 0.95 mmol/l, p < 0.05). Conclusion: The high prevalence of obesity both in elderly men and women and its strong association with chronic diseases causes economical and social burden for Hungary. Strategies and programs for weight maintenance as well as weight reduction must become a higher public health priority.