Introduction: Chagas disease is an endemic parasitic infection in Latin America transmitted by triatomines. It is associated with risk factors such as poverty and rurality. After acute infection, a third of patients will present target organ involvement (heart, digestive tract, central nervous system). The remaining two thirds remain asymptomatic throughout their life. Pharmacological immunosuppression breaks the balance between the immune system and the parasite, favoring its reactivation. Clinical case: We present the case of a 58-year-old man from a Colombian rural area with a diagnosis of multiple myeloma refractory to the first line of treatment who required a new chemotherapy scheme and consolidation with autologous stem cell transplant. During the post-transplant period, he suffered from febrile neutropenia. Initial microbiological studies were negative but the peripheral blood smear evidenced trypomastigotes in blood. With a diagnosis of acute Chagas disease in a post-transplant patient, benznidazole was started. The evolution of the patient was satisfactory. Conclusions: Positive serology prior to transplantation makes it necessary to rule out reactivation of the pathology in the setting of febrile neutropenia. More studies are required to determine tools for estimating the probability of reactivation of the disease and defining the best cost-risk-benefit relation for the prophylactic therapy.