The transcription factor complex hypoxia-inducible factor (HIF)-1 regulates the adaptation of macrophages and dendritic cells to hypoxic and inflammatory conditions. Bone marrow derived dendritic cells (DCs) are always contaminated with macrophages, which are known to react to inflammatory stimuli with a dramatic induction of HIF-1 activity. This could mislead to the assumption that the transcription factor HIF-1 is important for the adaption of dendritic cells to inflammatory hypoxia. To analyze if the observed effects in our bone marrow derived cell cultures were caused by DCs we differentiated cells with and without Interleukin-4 (IL-4). IL-4 is the major cytokine driving DC differentiation. The lack of IL-4 during differentiation led to increased numbers of macrophages while the number of mature dendritic cells was decreased. Then, DC cultures from control and HIF-1a knockout mice were cultivated with and without IL-4. The cells were compared in their response to bacterial lipopolysaccharides under normoxia and hypoxia. No differences in HIF-1a protein or HIF-1 target gene expression were detected between cell cultures with and without IL-4. LPS-stimulation led to similar activation of HIF-1 and was independent of DC purity. Furthermore, no significant differences in gene expression of the inflammatory cytokines IL-1b or TNF-a were obvious after differentiation under the distinct conditions. Thus, contaminating macrophages in DC cultures have a negligible influence on hypoxia and inflammation induced HIF-1 activation in dendritic cells.