We present a case of beta-thalassemia intermedia involving a 13-year-old boy of Northern European descent. His mother, father and older sister have normal hematologic indices. Molecular studies demonstrate that the proband carries a novel mutation of the beta-globin gene initiation codon (ATG-->AAG) which should give rise to beta(0)-thalassemia trait. The possibility of non-paternity was excluded, indicating that the novel mutation was the result of a de novo event. A review of the literature indicates that mutations involving the beta-globin gene initiation codon can give rise to a more severe phenotype than is generally associated with most other beta(+) or beta(0) mutations.