The prevalence of overweight and obesity in most developed and developing countries have been increasing markedly over the past two decades. This increase includes all ages, genders, racial and ethnic groups, income, and educational levels. This study examined the prevalence of overweight and obesity among adults aged 25–55 years in Shiraz (Southern Iran). The data are based on a random multistage sample survey of 2282 married adults (1141 pairs) living is Shiraz, whose heights and weights were measured in the 2002–2003 academic year. The prevalence of overweight or obesity (body mass index ≥ 25) was 49.7% in men and 63.9% in women. The prevalence of obesity (body mass index ≥ 30) was 10.5% and 22.5% in men and women, respectively, which shows an increased secular change of 5.8% in men and 17.4% in women during a 14-year period. Overweight and obesity are common in Iran. Obesity and overweight were significantly more common among women than among men (P-valve = 0.000). There is a need to establish programmes for prevention and treatment of obesity especially Iranian's women.