Except for two reports on Lebanese immigrants, there have been no studies on the major histocompatibility [MHC] antigens in the Lebanese population. We describe the frequency and distribution of MHC class I antigens present in the A, B and C loci based on data obtained from 200 healthy unrelated individuals from different parts of Lebanon. The highest gene frequencies were as follows:A2 [24.8%], B35 [17.9%] and Cw4 [18.6%], making this haplotype the commonest. Comparison of genetic distances revealed a pattern closer to the Caucasoid population than to the Mongoloid, Oriental or Black populations