The risk factors for and incidence of central nervous system involvement at first relapse in adult patients with acute myeloid leukemia have not been established. This single-center study analyzed the prognostic factors for and cumulative incidence of meningeal relapse in 458 adult patients achieving complete remission. Before 1990, patients received old chemotherapy approaches without stem cell transplantation that often included prophylactic intrathecal chemotherapy. Since 1990, modern protocols included stem cell transplantation without intrathecal prophylaxis. Meningeal relapse occurred in 6 patients (overall 5-year cumulative incidence 1.3%). The 5-year cumulative incidence of meningeal relapse in patients treated with old and modern protocols were 3.9% and 0.3%, respectively. Univariate and multivariate analyses showed that the chemotherapy approach was the main prognostic factor for central nervous system relapse (P=0.02). This study shows an extremely low incidence of meningeal relapse in adult patients with acute myeloid leukemia treated with modern protocols including stem cell transplantation without intrathecal prophylaxis.