Background Immunotherapy is now considered as the new pillar in treatment of cancer patients. Dendritic cells (DCs) play an essential role in stimulating anti-tumor immune responses, as they are capable of cross-presenting exogenous tumor antigens in MHCI complexes to activate naïve CD8+ T cells. Analgesics, like non-steroid anti-inflammatory drugs (NSAIDs), are frequently given to cancer patients to help relieve pain, however little is known about their impact on DC function. Methods Here, we investigated the effect of the NSAIDs diclofenac, ibuprofen and celecoxib on the three key processes of DCs required for proper CD8+ cytotoxic T cell induction: antigen cross-presentation, co-stimulatory marker expression, and cytokine production. Results Our results show that TLR-induced pro- and anti-inflammatory cytokine excretion by human monocyte derived and murine bone-marrow derived DCs is diminished after NSAID exposure. Conclusions These results indicate that various NSAIDs can affect DC function and warrant further investigation into the impact of NSAIDs on DC priming of T cells and cancer immunotherapy efficacy.