A prospective, randomised study was carried out in 135 patients to determine whether the time of removal of continuous sutures in the relief of post-operative astigmatism had any effect on subsequent changes in cylinder power or axis. After uncomplicated extracapsular cataract extraction with a corneal section and continuous 10/0 nylon suture, patients with more than 3 dioptres of cylinder were allocated to have their suture removed at 6, 9 or 12 weeks post-operatively. Visual and optical outcome were assessed 1 week after suture removal and at 6 months. Although the time of removal did not affect the change in cylindrical power, the subsequent refraction was more stable when the suture was removed at 12 weeks. However, initial against-the-rule astigmatism did not significantly change after suture removal and resulted in an unsatisfactory final prescription. Suture removal should therefore be performed at 12 weeks, glasses should not be prescribed early, and a poor outcome may be anticipated in those initially against-the-rule.