Thirty legs in nineteen patients, eleven with bilateral and eight with unilateral chronic anterior-compartment syndrome, were treated by fasciotomy. In addition, five of these patients (six legs) had compression of the superficial peroneal nerve: two before and three after fasciotomy. One patient also had lateral compartment syndrome in one leg. The patients who had compression of the superficial peroneal nerve were relieved by partial fasciectomy and fasciotomy of the lateral compartment. In one of these patients, with bilateral nerve compression, both superficial peroneal nerves were anomalous. The patient who had lateral compartment syndrome was relieved by fasciotomy of this compartment. Two patients required a second fasciotomy due to recurrence of the chronic compartment syndrome. At an average length of follow-up of twenty-five months after fasciotomy for anterior compartment syndrome, functional capacity was unlimited or increased in eighteen patients (twenty-eight legs) and was unchanged in one patient (two legs) who had had compression of the superficial peroneal nerve. The intramuscular pressures in the anterior compartment were normal at rest as well as during and after exercise eight months after the original fasciotomy in twenty-eight legs and eight months after the second fasciotomy in two legs.