Sexual dysfunction affects a large part of patients suffering from multiple sclerosis, but some aspects of its clinical presentation and aetiology are not clearly defined yet. In an unselected sample of 108 patients with definite multiple sclerosis we investigated the relationship between symptoms of sexual dysfunctioning and sphincteric dysfunction, patients' and disease characteristics, disability and neurological impairment, psychological and cognitive functioning. Sexual dysfunction directly correlated with presence of physical disorders (r=0.37, P=0.0004), low educational level (r=0.32, P<0.002), disability (r=0.31, P<0.003), age at onset of symptoms (r=0.30, P<0.003), sphincteric dysfunction (r=0.30, P<0.003), age (r=0.30, P<0.004), depression (r=0.29, P<0.005), fatigue (r=0.29, P=0.005), cognitive deterioration (r=0.26, P<0.01), primary-progressive course of disease (r=0.25, P<0.02), neurological impairment (r=0.25, P<0.02), marriage (r=0.24, P<0.02), anxiety (r=0. 23, P<0.03), male gender (r=0.22, P=0.03) bladder dysfunction (r=0. 29, P<0.04), and unemployment (r=0.21, P<0.04). Sexual dysfunction correlated inversely with relapsing - remitting course of disease (r=-0.31, P<0.002). No correlation was found between sexual dysfunction and bowel dysfunction, duration of disease, secondary-progressive course of disease, number and frequency of sexual intercourses in the last year, number of partners, number of exacerbations in the last year, number of months since last exacerbation, masturbation, and fertility. In conclusion, the association between sexual dysfunction and sphincteric dysfunction indicates a common aetiology corresponding to the frequent involvement of the spinal cord in multiple sclerosis, but the concomitant correlation between sexual dysfunction and other variables suggests the possible aetiological role of physical, psychological and sociological factors as well.