Four hundred and seventeen patients with operable breast cancer treated by simple mastectomy were randomly allocated to have node sampling or total axillary clearance. There was no significant difference in the incidence of node positivity. One hundred and thirty-five patients had node sampling and were randomized at the completion of this procedure to have axillary clearance or to have no further surgery. All node positive patients who went on to have a clearance had positive samples, confirming the accuracy of the sampling technique.