Thalassemias are a group of genetic hemolytic disorders with varying phenotypes. In this study, the frequency of a globin gene deletions was studied in the b-thalassemia trait, the mildest form of the disorder. Eleven out of 33 (33%) individuals were positive for a -3.7 kb deletions. None of the subjects was positive for the Southeast Asian deletion. Such a high frequency for a deletions has not been reported earlier in thalassemia minor. Hematological parameters are compared, and implications of this finding for genetic counseling are discussed. Am.