This randomised, crossover study compared patient-controlled sedation using boluses of propofol and patient-maintained sedation using a target-controlled infusion of propofol. Twenty-three patients aged 18-35 years having surgical removal of bilateral third molar teeth under local anaesthesia during two separate visits were studied. In the majority of patients, both techniques provided moderate sedation, good operating conditions, stable physiological parameters and a high degree of patient satisfaction. Two patients became over-sedated during patient-controlled sedation. The time taken for titration to adequate sedation was longer with patient-maintained sedation than with patient-controlled sedation [mean (SD) = 8.6 (3.7) min vs. 5.7 (3.1) min, p < 0.005]. The mean overall propofol consumption was similar with both techniques. The majority of patients preferred patient-maintained sedation to patient-controlled sedation, p < 0.05.