BACKGROUND AND AIMS: The key role of the brain-gut axis in the pathophysiology of irritable bowel syndrome (IBS) has been recognized. The aim of this study was to assess the possible association between IBS, neuroendocrine markers, and psychological features. METHODS: One hundred and twenty-five consecutive IBS patients and 105 healthy subjects were enrolled. Plasma serotonin, plasma and urinary cortisol, and plasma neuropeptide Y levels were evaluated. All patients were given a questionnaire to assess IBS symptom severity. In 66 patients, a psychodiagnostic assessment was carried out. RESULTS: A high incidence of specific psychological features, including state anxiety (69.69 %), trait anxiety (54.54 %), obsessions and compulsions (28.78 %), was observed in IBS patients. A positive correlation between neuropeptide Y and state anxiety (r = 0.287, p = 0.024) and simulation/social ingenuity (r = 0.269, p = 0.039) was found in these patients. In diarrhea-predominant IBS, plasma cortisol was linearly related to plasma serotonin (r = 0.5663, p < 0.001). CONCLUSIONS: In IBS patients, a significant correlation was found between specific psychological features and neuroendocrine markers, especially plasma cortisol and neuropeptide Y; in diarrhea-predominant IBS, a correlation between plasma cortisol and serotonin was found, although it needs to be confirmed in more extensive cohorts.