The biomechanics of the Murphy procedure for correction of equinus in cerebral palsy are presented. A series of 79 surgical procedures on 48 patients, with a follow-up period of from one to four years, is reviewed. Correction of equinus was succeswful in 89-9 per cent of the procedures. Using the Murphy procedure the following advantages over other methods of correction are anticipated: (1) no loss on 'push-off' in gait; (2) no loss of correction (recurrence) during longitudinal growth of the child, necessitating repeated surgery; and (3) no need for continual night bracing during the growth period.