Introduction: Spontaneous retroperitoneal hemorrhage from the use of enoxaparin is very rare but can be fatal. Although most cases are treated by conservative means, there may be a role for surgical intervention. Case report: We present the case of a 77-year-old man who developed a large retroperitoneal hemorrhage during treatment for pulmonary embolism and atrial flutter with enoxaparin in which supportive measures failed and necessitated surgical correction. Conclusion: This case adds to the growing number of cases of enoxaparin induced spontaneous retroperitoneal hemorrhage and the importance of surgical intervention when conservative management fails.