Background and Purpose- Hemorrhagic transformation (HT) after acute ischemic stroke may cause severe neurological deterioration and affects functional outcome. Identifying patients most likely to suffer from this complication could potentially be used for future treatment selection. Reperfusion after endovascular therapy could be associated with different risk factors for HT than intravenous thrombolytics as these treatments largely differ. In this study, we aimed to identify clinical and imaging markers that are associated with HT subtypes in the MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) population. Methods- In this post hoc analysis, all patients with follow-up imaging were included. HT was classified according to ECASS II (European Cooperative Acute Stroke Study). Variables with an association of <0.1 were included in the multivariable logistic regression to identify clinical and radiological variables associated with petechial hemorrhagic infarction, parenchymal hematoma (PH), and symptomatic intracranial hemorrhage. Results- Of the 478 out of 500 included patients in this subanalysis, 46% had HT (n=222). Of these, 66% had hemorrhagic infarction (n=147) and 34% PH (n=75). Symptomatic intracranial hemorrhage was observed in 7.3% (n=35) of all patients. Baseline National Institutes of Health Stroke Scale (odds ratio [OR], 1.05,95% CI, 1.01-1.09 per point) and absent/poor collaterals (OR, 1.90; 95% CI, 1.05-3.42) were significantly associated with hemorrhagic infarction. Increased systolic blood pressure (OR, 1.17; 95% CI, 1.05-1.31 per 10 mm Hg) and atrial fibrillation (OR, 1.94; 95% CI, 1.08-3.48) were associated with PH. Increased systolic blood pressure (OR, 1.28; 95% CI, 1.12-1.48) and antiplatelet use (OR, 2.6; 95% CI, 1.08-6.3) were associated with symptomatic intracranial hemorrhage. Conclusions- Clinical and imaging stroke severity parameters were associated with HT, both in hemorrhagic infarction and PH, whereas baseline patients characteristics like systolic blood pressure, atrial fibrillation, and antiplatelet use were only associated with PH or symptomatic intracranial hemorrhage. Clinical Trial Registration- URL: http://www.controlled-trials.com. Unique identifier: ISRCTN10888758.