Dendritic cells (DCs) can induce tumor- or pathogen-specific T cell responses in humans. We comprehensively compared the clinically available DC maturation stimuli for their ability to promote uniformly mature DCs that elicit higher levels of T cell responses. We compared the standard maturation stimulus, autologous monocyte-conditioned medium (MCM), with a synthetic double stranded RNA (poly I:C), soluble CD40 ligand trimer, and a defined cocktail of cytokines (TNF-alpha, IL-1 beta, IL-6) and PGE(2) to promote mature phenotype and function in human monocyte-derived DCs. The cocktail was the most efficient despite the lack of induction of IL-12p70. While these results support the use of the MCM-mimic cocktail in clinical DC immunotherapy trials, the roles of it's individual constituents remain to be completely defined.