The Wilms' tumor 1 (WT1) expression has been recognized in a substantial number of acute myeloid leukemia (AML) patients. Some studies indicated the association of diagnosed WT1 higher expression (WT1(H)) and poor outcome in the AML patients, while other studies had different opinions. Therefore, we performed a meta-analysis to evaluate the controversial prognostic significance of diagnosed WT1(H) in AML. Eligible studies were identified from several databases including PubMed, Embase, Web of Science, and the Cochrane Library (up to September 2014). The primary end point was overall survival (OS) and disease-free survival (DFS) was chosen as secondary end point. If possible, we would pool estimate effects (hazard ratio [HR] with 95 % confidence interval [CI]) of outcomes in both fixed and random effects models. Eleven studies, covering 1497 AML patients, were included in this meta-analysis. Pooled HRs indicated that diagnosed WT1(H) had a poor impact on the survival of AML patients (HR for OS, 1.37; HR for DFS, 1.38). Furthermore, diagnosed WT1(H) appeared to be an adverse prognostic indicator in adult AML (HR for OS, 1.43; HR for DFS, 1.41) and non-promyelocytic AML (non-M3 AML) (HR for OS, 1.46; HR for DFS, 1.41). Diagnosed WT1(H) had slightly but significantly poor prognostic impact on OS and DFS of patients with AML in total population and some specific subgroups.