A modified, laboratory-made carbon cup (small-scale Massmann) atomiser is described, with particular reference to the atomic-absorption determination of copper, lead and cadmium in water samples. Several parameters such as sample volume, time and temperature of the atomisation steps, and sample composition, have been investigated. It was found that injection of a 10-µl sample in one portion is the most convenient technique with respect to sensitivity and speed of operation. Addition of EDTA causes an enhancement of sensitivity, which is considerable when determining lead. The adsorption of these elements on the polyethylene containers has also been examined in order to evaluate possible errors that may arise after sample storage. The detection limits are 0·45 ng ml–1 of lead, 1·7 ng ml–1 of copper and 0·04 ng ml–1 of cadmium, and the average precision is ±3 per cent. in a single measurement. The method permits the direct and rapid determination of these elements in various water samples, which determinations are frequently required in pollution control.