Obesity is a chronic disease that is now a global epidemic. The numbers of obese people are exponentially rising in Europe, and it is projected that in Europe by 2010 there will be 150 million obese people. The obesity-related health crisis does not only affect adults, with one in four European children now overweight. Radiologists, both adult and paediatric, need to be aware of the magnitude of the problem, and obese patients cannot be denied radiologic evaluation due to their size. Missed diagnosis, appointment cancellation and embarrassing situations for patients when they are referred for a radiological examination for which they are not suitable are all issues that can be avoided if careful provision is made to accommodate the needs of the obese patient requiring radiologic evaluation. This paper will discuss the epidemiology of obesity and the role of radiology in the assessment of obesity and disorders of fat metabolism. The limitations obesity poses to current radiological equipment and how the radiologist can optimise imaging in the obese patient will be described. Dose reference levels and dose control are discussed. Examples of how obesity both hinders and helps the radiologist will be illustrated. Techniques and pre-procedural preparation to help the obese patient in the interventional suite are discussed.