As in all related with patellofemoral joint, it is not possible to discuss a consensus on the classification of patellofemoral joint diseases. These diseases sharing a wide range of characteristics at different age groups also have similar or even common characteristics. For nearly 40 years, classification systems based on a number of parameters have been developed within the purpose of classification of patellofemoral joint diseases. An ideal classification system should be comparable and a guide for clinicians in terms of treatment and useful, more importantly, in the clinical practice.