BACKGROUND: The purpose of this study was to examine the prevalence and distribution of unexpected antibodies detected in the Korean population with race-specific RBC panel cells. In spite of a relatively high prevalence of Dia and Mia antigen phenotype in the Korean and Southeast Asian population, there has been little documented research on the prevalence and clinical significance of anti-Dia and anti-Mia in Korea. METHODS: We analyzed the results of 17, 664 antibody screening tests performed during the recent 30-month period from March 2001 to September 2003. Antibodies were screened and identified by using LISS/Coombs gel card with DiaMed-ID system (DiaMed AG, Cressier, Morat, Switzerland) including Dia and Mia panel cells. RESULTS: The prevalence of unexpected antibodies was 1.2% (214/17, 664); antibodies detected most frequently were anti-Rh (74 patients), followed by anti-Lewis (21 patients) and anti-Dia (15 patients). Out of 6, 345 patients, anti-Mia was detected in three patients (0.047%). Anti-Dia and anti-Mia had the specificity of IgG. Anti-Dia was thought as an immune-mediated antibody, whereas anti-Mia was considered as a mixed type with immune and natural antibodies. CONCLUSIONS: This study shows that anti-Dia and anti-Mia antibodies are detected frequently in the Korean population; hence, it seems that Dia and Mia panel cells should be incorporated into antibody screening panels in Korea for safe transfusion.