Thirty-one polymyositis patients treated with low-dose corticosteroid were age and sex matched with 31 polymyositis patients treated with high-dose corticosteroid. Although disease severity at onset of the study was similar in the groups, no statistically significant difference in survival was found. The death rate in each group was greater than normal. The presence of dysphagia or severe muscle weakness lessened the chances of survival. Controlled trials with other drugs should be carried out.