BACKGROUND: Gastrointestinal stromal tumours (GIST) are mesenchymal tumours which mostly arise in the gastrointestinal tract showing positive CD117 immunohistochemical staining. In recent years, other locations such as the mesentery and the retroperitoneum have been reported. CASE: A 77-year-old woman presented with a pelvic mass, raising the suspicion of an ovarian or a uterine tumour. During laparotomy, a ruptured process arising from the uterus was seen and removed. Histologic features, immunophenotype and genotype of the tumour supported the diagnosis of a GIST. CONCLUSIONS: To the best of our knowledge, this is the first case of a primary GIST presenting as a uterine mass. Because of recent advances in GIST-therapy, making a correct diagnosis has major clinical implications.