Mixed affective episode is a prevalent mood disorder characterized by the coexistence or rapid alternation of manic and depressive symptoms, which is associated with significant suffering and high risk of suicide. Unfortunately, the current diagnostic classification of mixed affective episodes in the ICD-10 lacks a detailed definition with relevant subtypes. This inconsistency has significant negative implications for both research into the disorders in the bipolar spectrum and for clinical practice. For this reason there is a need for special attention on this diagnosis in the revisions of the diagnostic manuals. In this manuscript we suggest a set of clear diagnostic criteria and exhaustive subtypes for the mixed affective episodes aimed at the upcoming ICD-11. The defined syndrome and its subtypes are in close congruence with the suggested DSM-5 "mixed episode specifier", which is an advantage for common understanding and for research across the ICD/DSM border.