Heart transplantation is currently a procedure of choice for patients with advanced heart failure. Despite a continuous improvement in morbidity and mortality made to date, complications requiring hospitalization continue to be high. The main objective of this study was to describe complications that required hospitalization after a heart transplant, and the secondary objective is to evaluate its incidence according to age group in a cohort of heart transplant recipients in Argentina. A retrospective cohort study was carried out. One hundred and ninety-eight heart transplant recipients were consecutively included in the period between January 2010 and May 2019. During follow-up, 105 patients (53%) had at least one readmission, and the most frequent cause of cardiovascular readmission was graft rejection (31%), while infections were the most frequent non-cardiovascular causes (21%). Mortality density incidence was 8 (95% CI 5.4-11.7) per 100-patients/year for the group that had readmission and 1 per 100-patients/year (95% CI 0.4-2.8) for the group that did not have. We conclude that complications requiring hospitalization are frequent in transplanted patients and affect long-term survival. The main causes of readmission are graft rejection and infections, and they had similar incidence in the age groups we analyzed.