We conducted a study to determine the types and costs of drugs used by Nova Scotia senior citizens with multiple sclerosis (MS) compared with the types and costs of drugs used by all senior citizens in Nova Scotia. Administrative claims databases from the Nova Scotia Seniors Pharmacare program for persons aged 65 years or older were linked to the Dalhousie Multiple Sclerosis Research Unit (DMSRU) clinical database (1980-1994). Analyses compared persons with MS aged 65 years or older who attended the DMSRU at least once with the general population of senior citizens. Not all persons with MS attended the DMSRU. In aggregate, Pharmacare costs in 1993-1994 for patients with MS aged 65 years or older (N = 52) were $975.00 Canadian per capita compared with $590.00 Canadian for all senior citizens in Nova Scotia (N = 108,646). Thus average drug costs for the senior citizens with MS were 65% greater than those for all senior citizens covered by Nova Scotia's comprehensive, publicly funded Pharmacare program. Compared with other senior citizens, those with MS more frequently received alpha-blockers, anticholinergics, cholinergics, tricyclic antidepressants, anticonvulsants, antifatigue agents, antispasticity agents, and antibiotics for bladder infections.