In traumatic injuries and diseases of the knee joint establishing a correct diagnosis is a very important part of therapeutic management. In many cases it is not easy. The reason for this is the possibility of simultaneous injury of many different anatomical joint structures, and as a result the occurrence of clinical symptoms that vary in intensity and often overlap. In diagnostic procedures, the most important task is to establish which of the anatomical structures has been damaged as a result of acute or chronic trauma, and how extensive the loss of joint function actually is. Making a correct diagnosis in acute traumatic injuries of the knee should be done as quickly as possible. The present study contains an outline of diagnostic evaluation in traumatic injuries and diseases of the knee joint. Each part of this outline is fully discussed.