Introduction: Pain in the inguinal region, frequently spreading to the femur, is a common symptom with a variable differential diagnosis. Spontaneous iliopsoas hematoma is a rarely reported adverse effect of anticoagulation therapy that can present with pain in the hip, with or without previous injury or surgery at the region. This case report aims to remind clinicians of this rare condition that can result in major complications. Case Presentation: An 83 year old male patient presented to our Emergency Department with pain at the right hip which within a week expanded to the lower back and anterior femur. During clinical examination restriction of movement due to soreness was noted, the hip joint was kept in slight flexion, while there were no abnormal vascular findings. Medical history included a right-sided total hip replacement 8 years ago, chronic atrial fibrilation, chronic cardiac failure and hypertension. He was on anticoagulant (rivaroxaban) and anti-hypertensive regimen. Laboratory results showed low hematocrit (HTC) and hemoglobin (HB), elevated prothrombin time (PT) and increased international normalized ratio (INR). Imaging showed a large iliopsoas hematoma. Conservative treatment was decided. Subsequently, the hematocrit normalized, the hematoma regressed and the pain receded. Conclusion: Despite being a frequent cause of complain, pain of the hip, lumbar or femur region could be the result of a more complex pathology. Such cases should therefore not be overlooked but examined thoroughly, especially if presenting with suspicious signs or symptoms or in a setting of co morbidities. When complains are with regard to an area that has been operated on, as in our case, clinicians should not attribute all symptoms on the presence of prior surgery. Keywords: Anticoagulation, spontaneous hematoma, iliopsoas, total hip arthroplasty.