Diseases like rheumatoid arthritis and osteoarthritis are a major cause of disability and early retirement in the industrialised countries and, therefore, of considerable socio-economic significance. Cartilage covers the ends of the bones acting as a weight bearing, low friction, wear resistant tissue in the joints and possesses considerable structural relevance in connective tissues. It is known that the composition of cartilage is crucial for its function and that the complex network of the cartilage matrix, consisting primarily of collagen and proteoglycans (highly organized polysaccharides), is destroyed in the course of rheumatic diseases. This review is dedicated to the biophysical chemistry of healthy and diseased cartilage as well as the methods that are useful in cartilage research. It is the aim of this paper to show that not only classical methods of biochemistry and molecular biology are useful in cartilage research but also biophysical techniques and structural biology tools may help to improve the knowledge of cartilage structure and function. Both, basic sciences and medical applications are considered.