Twenty-seven consecutive patients with posterior tibial tendon insufficiency were treated with talonavicular arthrodesis as the primary stabilizing procedure. Twenty-six patients were followed a minimum of 12 and an average of 27 months. Twenty-four patients had either no pain or pain only after heavy usage. Eleven patients were completely satisfied with postoperative foot function, 13 were satisfied, with minor reservations, and 2 were satisfied, with major reservations. Results were rated as excellent in 10 patients, good in 14 patients, and fair in 2 patients. Successful arthrodesis was achieved in all patients, although one patient required two additional bone grafts. Progressive arthrosis in adjacent joints was noted in five patients, four of whom had arthrosis preoperatively. No deterioration of foot position was seen in any patient with follow-up as long as 5 years. An isolated talonavicular arthrodesis seems to offer patients with this disorder both reliable pain improvement and lasting stability.