This article reviews several aspects of the association between obesity and cancer. Current perspectives of cancers of the breast, endometrium, colon and prostate are described. Obesity is a growing problem in contemporary societies, due to the rapid adoption of a modernized lifestyle that results in increased carbohydrate and fat-rich dietary intake, reduced physical activity and extended life expectancy. More than half of adult Americans are overweight or obese, and so is the population of many other countries. There are several definitions for the state of obesity. The body mass index (BMI), which measures overall adiposity, is universally available, the easiest to determine, and therefore the most commonly studied. Anthropometric measurements of subcutaneous fat distribution, such as measurement of girth, circumference of the arms, hips and thighs, or of skinfolds in various body regions are also often used. They allow to categorize the distribution of subcutaneous fat into android and gynoid types (den Tonkelaar, Seidell et al., 1994; Huang, Willett et al., 1999). The android, or abdominal, fat is determined from the waist to hip ratio, and is of particular relevance to cancer. Increased body weight and fat are associated with high health risks, and therefore body fat distribution and BMI are major predictors of obesity associated risks (Calle, Thun et al., 1999; "Overweight, obesity, and health risk," Yanovski, 2000). These include diabetes mellitus type 2, coronary heart disease, sleep apnea and pulmonary dysfunction, stroke, diseases of the gallbladder, liver and the musculoskeleton, reproductive dysfunction, venous insufficiency, deep vein thrombosis, poor wound healing, and more (Pi Sunyer, 1993; "Overweight, obesity, and health risk", Yanovski, 2000). All these are associated with increased mortality, especially in individuals with other risk factors (Calle, Thun et al., 1999). Cancer is also associated with obesity (Garfinkel, 1985), and the present paper attempts to summarize current perspectives of this association, especially in cancers of the breast, endometrium, colon and prostate.