Forty-nine patients with posterior tibial tendon dysfunction (4 patients had bilateral involvement) were treated with orthoses. Forty feet were treated with molded ankle-foot orthoses, and 13 feet were treated with University of California Biomechanics Laboratory shoe inserts with medial posting. A total of 37 women and 12 men were included in the study. The mean follow-up period was 20.3 months (range, 8-60 months). The average age of the patients was 66 years (range, 42-89 years). Sixty-seven percent of patients had good to excellent results, according to a functional scoring system based on pain, function, use of assistive device, distance of ambulation, and patient satisfaction. The average period of orthosis use was 14.9 months (range, 1.5-29 months), with an average length of daily orthosis wear of 12.3 hours. One patient elected to undergo surgical treatment rather than continuing with long-term orthosis use. Thirty-three percent of patients had discontinued using the orthosis at the time of follow-up evaluation. Three patients were unable to wear the orthosis because of concurrent medical conditions. Nine patients stopped wearing the orthosis after experiencing discomfort and inconvenience. Although these patients continued to exhibit signs and symptoms of posterior tibial tendon dysfunction, they were not disabled enough to consider further treatment. Four patients tolerated orthosis treatment poorly and were treated surgically. Patients with posterior tibial tendon dysfunction can be treated by aggressive nonoperative management using molded ankle-foot orthoses or University of California Biomechanics Laboratory shoe inserts with medial posting. Surgical treatment can be reserved for patients who fail to respond to an adequate trial of brace treatment. Nonoperative management using an orthosis is particularly useful for elderly patients with a sedentary lifestyle or for patients at high risk because of medical problems.