Immunophenotyping of acute myeloid leukemia has controversial implications with regards to prognosis. Many associations have been described between individual antigen expression on myeloid blasts and prognosis, however few are consistent. Markers with a consistent prognostic association that have been demonstrated in more than one study have been CD13, CD14, and CD15. The association of the expression of CD11b with poor prognosis appears definite, as does CD7 expression. When compared with the expression of a single antigen, a pattern of antigen expression is likely to have a more significant relationship to prognosis. This is exemplified by the panmyeloid phenotype (expression of 5 myeloid antigens) which appears to be associated with a good prognosis and may differentiate a subgroup within an otherwise intermediate prognosis group of patients. Further analysis with the inclusion of novel antibodies and the combination of multiple antibodies to create further subgroups such as the panmyeloid phenotype will continue to enhance knowledge in this area.