Preservation of the spleen in patients with posttraumatic subcapsular hematoma is still controversial. To determine the best therapeutic approach for this type of splenic injury, we designed an experimental model of subcapsular hematoma of the spleen in dogs. A total of 23 subcapsular hematomas were caused in 19 dogs, which were followed both clinically and ultrasonographically for 12 weeks. Fifty-seven per cent of the hematomas resolved spontaneously; those that persisted (43%) were aspirated percutaneously with ultrasound guidance, after which they were all resolved. Our results support a conservative approach. When the hematoma does not resolve spontaneously, percutaneous ultrasound-guided aspiration may be considered.