Our objective was to assess the point prevalence and effects of clinically significant anxiety in patients with Multiple Sclerosis (MS). One hundred and fifty two consecutive patients with MS attending an outpatient clinic underwent neurological examination and were assessed for psychopathology with the Hospital Anxiety and Depression Scale, the 28 item General Health Questionnaire and a questionnaire probing suicidal thoughts or intent. Clinically significant anxiety, either with or without depression, was endorsed by 25% of patients, three times the rate for depression. Females were significantly more anxious than males. Anxiety co-morbid with depression, rather than anxiety or depression alone, was associated with increased thoughts of self harm, more somatic complaints and greater social dysfunction. Patients with increased psychopathology were not more likely to be taking psychotropic medication. The results provide preliminary evidence that anxiety, which may be often overlooked clinically, is a frequent accompaniment to depression, thereby adding to the morbidity associated with MS. The implications of the findings to MS patients' quality of life are emphasised.