The two main classification systems in psychiatry are represented by the Diagnostic and Statistical Manual of Mental Disorders (DSM) and by the International Classification of Diseases (ICD). The last version of the DSM has been published in 2013 by the American Psychiatric Association and it has been translated in Italian in 2014. The eleventh revision of the ICD by the World Health Organization has been completed in 2018, approved by the WHO General Assembly in 2019 and it is going to be translated in several languages. Although authors of the last editions of both manuals aimed to the harmonization, several differences still persist. In particular, the DSM has the global aim to be used in the scientific research settings, while the ICD aims to improve the clinical utility of the different diagnoses in the clinical practice. In the near future, all these features should be taken carefully in consideration in order to promote a real integration and harmonization between the two diagnostic systems.