There is a growing interest in using dendritic cells (DC) for vaccine approaches in the treatment of cancer and infectious diseases. This requires a reproducible method for the generation of large numbers of DC in a closed culture system suitable for clinical use and conforming to the current guidelines of good manufacturing practices. We designed a system in which the DC were generated in a closed system from adherent monocytes using Cell Factories (DC-CF). Monocytes were enriched from apheresis products by adherence and then cultured in the presence of AB serum or autologous plasma and GM-CSF and IL-4 for 6 days. The DC generated in Cell Factories were extensively compared to research-grade DC generated in conventional tissue culture flasks (DC-TCF). At day 6, the immature DC were harvested and the yield, the viability, the immunophenotype and the functional characteristics of the DC were compared.DC-CF and DC-TCF showed similar viability and purity and scored equally when tested for stability, dextran and latex bead uptake, in MLR and in the activation of influenza-specific memory cells after electroporation with influenza matrix protein 1 (IMP1) mRNA. These data indicated that large numbers of functional clinical-grade DC could be generated from adherent cells in a closed system using Cell Factories.