The records of the recovery pattern of 30 patients given atracurium 0.2-0.9 mg kg-1 were studied. Recovery of the sustained tetanic contraction did not follow an exponential curve as had previously been assumed. However, it did fit a logistic curve so that the plot of logit blockade against time was linear between 99% and 5% blockade. The results support the previous claim that the rate of recovery is independent of dose and that the effects of atracurium are not cumulative in the clinical dose range. The use of the logit transformation may also prove helpful in the analysis of the single twitch contraction during recovery from neuromuscular blockade by atracurium.