The results are presented from two external quality control surveys of cell counters in primary health care. The precision of haemoglobin measurements in the normal range was better than that obtained by conventional haemometers. The analytical quality of leucocyte analyses was about the same as that performed by hospital instruments. The precision of cell counters with respect to thrombocytes was poorer than that obtained on hospital instruments, especially in the lower level. Celldyn and Sysmex instruments performed best among the instruments examined. Reliable cell counter results were associated with medical laboratory technicians as operators of the instruments. To improve the analytical quality of the laboratory in primary health care, it appears necessary to establish an external quality assurance programme, including a laboratory consultancy service.