The polymorphism in the factor XIII A-subunit gene (FXIII Val34Leu) has been recognized as a risk factor for primary intracerebral hemorrhage (PICH). In addition, FXIII Val34Leu has a significant ethnic heterogeneity. FXIII Val34Leu was detected in 41.7-54.8% of the Westerners, but in 2.5% of the Asians. We aimed to evaluate the prevalence of FXIII Val34Leu in patients with PICH and in healthy controls among Koreans. We recruited 58 in-patients with PICH, defined by brain computed tomography or magnetic resonance imaging, and 48 controls matched for age, sex, and risk factors for cerebrovascular diseases. Genomic DNA was extracted from blood. A 183-bp fragment of exon 2/intron B of the factor XIII Asubunit gene was amplified by polymerase chain reaction (PCR). The factor XIII genotype was determined through a single-stranded conformational polymorphism. Fifty-eight patients and 48 controls showed the same band patterns on SSCP. In addition, we directly sequenced six random-selected DNA segments using DNA auto-sequencer. In conclusion, the results of this study suggest that FXIII Val34Leu be absent or rare both in patients with PICH and in healthy controls among Koreans.