A retrospective analysis of the clinical and haematological characteristics of patients diagnosed as having juvenile chronic granulocytic leukaemia between 1971 and 1986 was carried out. Thirty-three children were identified who were between the ages of 18 weeks and 8.8 years at diagnosis. The disease was more frequent in boys than girls (23:10). The most common presenting symptoms were skin rash (58%) and bleeding manifestations (45%). All patients had some degree of splenomegaly and in 88% this was more than 3 centimetres below the costal margin. Hepatomegaly and lymphadenopathy were also frequent findings. Anaemia was common and leucocytosis an invariable finding with a white cell count above 50 x 10(9) 1-1 in 42%. Monocytosis was found in 78%. Haemoglobin F measurements were available in 31 children and above 10% in 22 (67%). No child had the Philadelphia chromosome or monosomy 7. Thirty children were treated with chemotherapy, with a variable degree of symptomatic improvement. Twenty-nine patients had died with a median survival time of 5 months. The commonest cause of death was complications of bone marrow failure and no child developed acute leukaemia. Presenting characteristics associated with a longer survival period were age less than 6 months (P = 0.02), female sex (P = 0.02), HbF less than 10% (P = 0.0004) and the absence of bleeding manifestations (P = 0.03). We conclude that the prognosis for children aged over 6 months, with a raised HbF level is very poor, and that, in the absence of possible bone marrow transplantation, consideration should be given to novel treatment approaches for these patients.