The clinical and radiological findings, management, and outcomes in 35 patients with traumatic interhemispheric subdural haematoma (ISH) were reviewed retrospectively. Twenty-five patients had favourable outcomes and 10 had poor outcomes. All patients were treated conservatively for ISH. Univariate analysis found that the Glasgow Coma Scale (GCS) score (p<0.001), hypovolemic shock (p=0.018), skull fracture (p=0.008), convexity or posterior fossa subdural haematoma (p=0.008), and subarachnoid haemorrhage (SAH) were correlated with outcome (p<0.001). Multivariate analysis showed that GCS score (p=0.031; odds ratio [OR], 0.6; 95% confidence interval [CI], 0.3–0.9) and the presence of SAH (p=0.023; OR, 14.2; 95% CI, 1.5–138.2) were significantly related to poor outcome. This study provides important information on the clinicoradiological findings and prognoses in patients with traumatic ISH.