The aim of the investigation was to study most frequent clinical variants of myocardial infarction (MI) onset at a multifield hospital, as well as some features of its course and outcomes in patients undergoing treatment at different departments. The study found that the onset of intrahospital MI was often atypical, and that atypical onset was most frequent in cases of myocardial necrosis in patients undergoing treatment in surgical and therapeutic departments. The clinical picture, ECG data, and outcomes were analyzed in patients with MI whose onset took place at different hospital departments. The study revealed that the course of atypical variants of intrahospital MI, especially in surgical and therapeutic noncardiological patients, was more severe than in patients of cardiological departments.