Seventy-seven patients with idiopathic frozen shoulder syndrome were included in a prospective study to compare the effect of intensive physical rehabilitation treatment, including passive stretching and manual mobilization (stretching group) versus supportive therapy and exercises within the pain limits (supervised neglect group). There were no significant differences in age, sex, time elapsed since onset, and disease severity at inclusion. All patients were followed up for 24 months after the start of treatment. In the patients treated with supervised neglect, 89% had normal or near-normal painless shoulder function (Constant score > or =80) at the end of the observation period. This end result was reached by 64% within 12 months. In contrast, of the group receiving intensive physical therapy treatment, only 63% reached a Constant score of 80 or higher after 24 months. Both the level of the Constant score at the end of the study and the moment a Constant score of 80 or higher was reached confirm that supervised neglect yields better outcomes than intensive physical therapy and passive stretching in patients with frozen shoulder.