Intensive chemotherapy (IC) used to be a common treatment approach for patients with higher-risk myelodysplastic syndromes (MDS) or acute myeloid leukemia after MDS (sAML). We conducted a retrospective analysis of 299 patients, including a matched pair analysis comparing 96 patients receiving IC with 96 patients not undergoing IC, in order to evaluate the impact of IC on overall survival (OS) and to identify factors that influence remission rates and OS. Complete remission (CR) after first induction chemotherapy was reached in 50% of patients. Parameters influencing the probability of achieving CR were blast count in the bone marrow (< 30%), age < 65 years, presence of Auer rods, duration of antecedent MDS shorter than 6 months, and timing of IC in relation to first diagnosis. The difference in survival time was not significantly better for patients receiving IC (median OS 12.7 months vs. 7 months). Parameters favorably influencing survival were the presence of Auer rods, age below 60 years, blast count below 30%, IC given shortly after first diagnosis, and achievement of CR. On multivariate analysis, achieving CR, presence of Auer rods, and percentage of blasts below or above 30% significantly influenced median survival. Relapse occurred in 63% of patients after a median of 9.9 months with a median survival of 7.6 months. Considering the high relapse rate and short survival, we conclude that intensive chemotherapy is not promising for high-risk MDS or sAML.