•Iliopsoas hematoma with resultant femoral nerve palsy is a rare phenomenon for which the optimal treatment is unclear.•PubMed, Embase, and Cochrane database review yielded 122 articles containing 174 distinct cases of the syndrome.•49% of all cases resulted in persistent motor deficit – 34% of those treated surgically and 66% of those treated conservatively.•Disparate data presentation prevented direct statistical comparison of patients treated conservatively versus surgically.•Based upon review, surgical treatment is usually reserved for larger hematomas with progressive or severe neurological symptoms. Iliopsoas hematoma with femoral nerve palsy is a rare phenomenon with no consensus treatment algorithm. The objective of this study was to perform a systematic review of all reported cases of femoral nerve palsy secondary to iliopsoas hematoma to better elucidate it's optimal treatment. Queries of the PubMed, Embase, and Cochrane databases were performed for reports available in English of femoral nerve palsy secondary to iliopsoas, psoas, or iliacus hematoma. 1491 articles were identified. After removal of duplicated publications and review of abstract titles via a majority reviewer consensus, 217 articles remained for consideration. Dedicated review of the remaining articles (including their reference sections) yielded 122 articles representing 174 distinct cases. Clinical data including patient age, sex, medical history, use of pharmacologic anticoagulation, sensory and motor examination at presentation and follow-up, hematoma etiology and location, time to intervention, and type of intervention were collected. Descriptive statistics were generated for each variable. Femoral nerve palsy secondary to iliopsoas hematoma occurred at a mean age of 44.5 years old. A majority of patients (60%) were male, and a majority of hematomas (54%) occurred due to pharmacologic anticoagulation. Most hematomas (57%) were treated conservatively, and almost half (49%) – regardless of treatment modality - resulted in persistent motor deficits at final follow-up. A minority of patients treated surgically (34%) had residual motor deficit at final follow-up, while 66% of those treated medically had resultant motor deficits, although no direct statistical comparison was able to be performed. The disparate available data on iliopsoas hematoma with femoral nerve palsy precludes the completion of a true metanalysis, and therefore any conclusions on an optimal treatment algorithm. Based on review of the literature, small to moderate hematomas are often treated conservatively, while larger hematomas with progressive neurological symptoms are usually managed with a percutaneous decompression or surgery. IV