Obesity affects over 20% of the UK's adult population and its prevalence is rising. Obesity can lead to a variety of musculoskeletal problems and is independently associated with locomotor disability and joint pain. Obesity increases the risk of radiographic knee osteoarthritis (OA), but has a lesser effect on disease progression. The association with hip and hand OA is weaker, but implies that excess adipose tissue produces humoral factors, altering articular cartilage metabolism. It has been postulated that the leptin system could be a link between metabolic abnormalities in obesity and increased risk of OA. Although obesity was initially thought to increase the risk of rheumatoid arthritis (RA), further studies showed, that heavier patients with RA have less radiological disease progression and possibly better survival. On the other hand, obesity is strongly associated with hypeuricaemia and gouty arthritis. High body weight correlates independently with metabolic syndrome and may contribute to increased cardiovascular morbidity in patients with gout. Weight reduction should be an important part of treatment for OA and gout. Because obesity at a young age correlates with the development of OA and gout in later life, preventive public health strategies aimed at lowering the incidence of obesity are of most importance.