We investigated the clinical profile, etiological factors, neuropsychological features and radiological characteristics of 17 cases of striatocapsular infarction (SCI). SCI was defined as the following CT criteria: the area of infarction included the internal capsule and striatum, the maximum diameter of the lesion exceeded 2.0 cm without cortical involvement. There were 9 men and 8 women with mean age of 58 years. Five patients had lesions mainly involving the caudate head (anterior type) and the other 12 had lesions mainly involving the putamen (lateral type), 6 with left side lesion and 6 with right side lesion. Motor weakness was observed in all patients, and the upper extremities were preferentially involved, while in 9 patients face, upper and lower extremities were simultaneously involved. Etiological investigation revealed that 8 patients were cardioembolic stroke, 2 were artery-to-artery embolism and 2 were MCA stem occlusive disease, while the remaining 5 were undetermined. When compared with patients with lacunar infarction (LI), patients with SCI had significantly more frequent cardioembolic sources (47% vs 17%, p < 0.05) and less frequent hypertension (41% vs 80%, p < 0.01). In acute phase, neuropsychological abnormalities were found in 15 patients. Anterior type patients had psychiatric symptoms such as abulia, depression and agitation, while left lateral type patients had aphasia and right lateral type patients had hemispatial neglect or anosognosia. These symptoms gradually improved, although in most patients subtle abnormalities lasted over chronic phase. In 11 out of 13 patients who underwent SPECT using 99mTc-HMPAO, blood flow was decreased in overlying cerebral cortex besides the infarcted area.(ABSTRACT TRUNCATED AT 250 WORDS)