Background. Gastrointestinal complications are a well-documented source of morbidity and mortality after heart and lung transplantation. Methods. We report on two patients who presented with gastric perforation caused by mucormycosis during the first 2 months after heart-lung and heart transplantation. Results. In the first patient, the clinical presentation was insidious and the diagnosis was made at an advanced stage of the disease. Despite surgery and aggressive antifungal treatment, the patient died. In the second patient, the diagnosis was made promptly, but despite antifungal treatment, he presented with gastric perforation within a week. Conclusions. These cases illustrate that fungal invasive disease may be a cause of early gastrointestinal perforation after solid organ transplantation.