Abstract Background Type 2 diabetes mellitus (T2DM) is a highly heterogeneous entity, with multiple subgroups differing by clinic presentation, disease progression and risk of complications such as myocardial infarction (MI). A new T2DM phenotyping classification has been recently proposed to help to improve treatment tailoring and target early treatments, and we aimed to identify the prevalence and characteristics of the new phenotypes. Methods All consecutive adults with a history T2DM hospitalized in a french Coronary Intensive Care Unit for an acute MI between February 1st, 2021 and January 31st, 2023 were included. Clusters were based on six variables (glutamate decarboxylase antibodies, age at diagnosis, BMI, HbA1c, and homoeostatic model assessment 2 estimates of β-cell function and insulin resistance). We stratified patients into five subgroups : 1/ SAID=severe autoimmune diabetes; 2/ SIDD=severe insulin-deficient diabetes; 3/ SIRD=severe insulin-resistant diabetes; 4/ MOD=mild obesity-related diabetes; and 5/ MARD=mild age-related diabetes. Results Among the 266 patients included, characteristics according to diabetes phenotypes are summarized in the Table. Conclusions Our prospective study showed that in real-world T2DM patients with acute MI, unclassical phenotypes, i.e. hyperinsulinaemic and insulinopaenic were common. Given the large discrepancies in characteristics, our findings suggest the relevance of the new substratification. However, its clinical utlity and translation in tailored treatment strategies and prognosis remains to be determined.Table.