Computerized tomography and magnetic resonance imaging allow the accurate diagnosis in stroke and distinction of ischemic from hemorrhagic lesions. However, clinical diagnosis is still critical where neuroimaging techniques are not available, especially to establish first-aid measures in a stroke patient. In this prospective study of 300 patients with stroke, the diagnosis of ischemic and hemorrhagic strokes was made as an informal bedside diagnosis prior to neuroimaging. The accuracy of bedside diagnosis was also compared with the results of the Allen and Siriraj stroke scores. Then, the reliability of these scores and our informal bedside diagnosis, along with the final diagnosis, were compared with each other. Our informal bedside diagnosis was correct in 250 of the 300 patients (83.3%). The diagnostic sensitivity and positive predictive value (PPV) of bedside diagnosis for ischemic stroke were 87.8% and 86.0% and for intracerebral hemorrhage 75.7% and 78.5%, respectively. Sensitivity and PPV for every cut-off value of the Allen and Siriraj stroke scores were less than that of sensitivity and PPV of informal bedside diagnosis. When the receiver operating curves obtained from the Allen and Siriraj stroke scores were compared, the Allen stroke score was found to be a better predictor in the final diagnosis. Our data suggest that an informal bedside diagnoses is as good as diagnoses made on certain intracerebral hemorrhages and on certain ischemic strokes by the Siriraj and Allen stroke scores; when compared, the Allen score seems to be better than the Siriraj stroke score. Hence, the use of both scores is recommended in epidemiologic studies as a screening tool as suggested by previous studies employing other diagnostic tools in clinics.