Polyps are considered to develop as an end result of an inflammatory process. Cytokines and chemokines in the respiratory mucosa may be a key to polyp pathophysiology. The main objective was to identify IL-5, IL-6, IL-12, RANTES, IFN-gamma and Fractalkine in humans on the protein level in nasal polyps and mucosa from the inferior turbinate (IT). Furthermore, the cytokines and chemokines RANTES and Fractalkine were analyzed in plasma. Tissue homogenates and plasma from 13 patients were analyzed by the ELISA technique. All the patients had longstanding nasal/paranasal polyposis. Fractalkine was detected in polyps and IT in two different patients. IL-5 was expressed in polyps and IT. IL-6 was expressed in all patients with a higher level in polyps than IT. IL-12 was present in plasma, polyps and IT, though at an increased level in polyps. RANTES was present at a higher level in plasma than in polyps and IT. IFN-gamma was detectable in polyps and IT. Fractalkine is detected in nasal polyps, which is a new observation. The overall results indicate a mixed T(H)1/T(H)2 cytokine profile in nasal polyps. RANTES and IL-12 are strongly present in plasma, suggesting an ongoing inflammatory "drive". IL-6 and IL-12 are up-regulated in polyps versus the IT. Up-regulation of IL-6 may be explained by increased fibroblast activity dependant on an ongoing local inflammation possibly initiated by an infection. IL-5, RANTES and IFN-gamma are equally represented in polyps and IT, indicating equilibrium between the nasal polyps and surrounding tissue, and that an up-regulation of cytokines in the polyp indicates a potential for polyp growth.