DiGeorge syndrome, a developmental defect of the third and fourth pharyngeal pouches, is characterized by aplasia or hypoplasia of the thymus and parathyroid glands and by conotruncal cardiac malformation. This syndrome is usually associated with deletion of long arm in chromosome 22 (22q11-). We experienced a case of partial DiGeorge syndrome in a 2-month-old male who had hospitalized because of recurrent hypocalcemic tetany and tetralogy of Fallot. Immunologic studies revealed the decreased percentage of T lymphocyte and increased percentage of B lymphocyte. Chromosomal study with high resolution banding, showed 46, XY, 22q13 deletion. We report a case of partial Digeorge syndrome with a brief review of literatures.