Spontaneous recovery, and recovery following neostigmine 20, 35 or 50 μg.kg^−1^ administered at 10 or 25% of recovery of the first twitch of the train‐of‐four, was assessed in 80 patients after rocuronium administration under continued isoflurane anaesthesia. In an additional 40 patients, isoflurane administration was discontinued and neostigmine 35 or 50 μg.kg^−1^ was given at 10 or 25% recovery. The administration of neostigmine reduced the recovery times significantly. A neostigmine dose of 20 μg.kg^−1^ resulted in slower recovery compared with the higher doses, particularly when reversal was attempted at a first twitch height of 10%. Higher doses of neostigmine given at a first twitch height of 25% resulted in rapid reversal of block [mean (SD) times of 7.0 (4.8) and 6.4 (1.9) min with the 35 and 50 μg.kg^−1^ doses, respectively, for attaining a train‐of‐four ratio of 0.8]. Discontinuing isoflurane did not alter recovery times. The incidence of emetic symptoms did not differ between groups, including one group that received atropine instead of glycopyrronium in combination with neostigmine. We conclude that rocuronium block can be antagonised safely using a neostigmine dose of 35 μg.kg^−1^, although recovery may be slightly slower if administered at a first twitch of 10% of control.