The presence of neuropeptide-containing sensory, parasympathetic and sympathetic nerves in human nasal mucosa is well established. However, information regarding the neuropeptide distribution in nasal polyps is still lacking. The aim of this study was to compare immunohistologically the presence and distribution of substance P (SP), vasoactive intestinal peptide (VIP) and bombesin-flanking peptide (BFP) in normal nasal mucosa and nasal polyps. The expression was studied using Formalin-fixed and paraffin-embedded biopsy sections from 20 patients with nasal polyps and 10 controls with normal nasal mucosa from the anterior part of the inferior turbinate. Indirect immunohistochemistry (APAAP method) with mono- and polyclonal antibodies was used. None of the control group but 5 patients of the nasal polyp group had an atopic disease. Comparing localization and intensity of the immunohistological reaction in nasal mucosa and nasal polyp tissue, there was no difference in the expression of the three neuroendocrine substances. There was no difference of expression in the polyposis group itself concerning allergic and nonallergic subjects. The results indicate that VIP, SP and BFP have an equal distribution in nasal polyps and normal nasal mucosa.