Retinoblastoma is a rare malignant tumour in the retina usually presenting before 3 years of age. In Sweden, 6-7 new cases are diagnosed each year. The medical treatment is highly specialized, very effective, with a survival ratio of almost 100%. Very little was known about the emotional and psychosocial effects on the parents and the patients themselves. This study includes all children diagnosed in Sweden between 1992 and 1994. The parents and children were included in our longitudinal support programme immediately after the diagnosis was made. This paper deals with the following topics: how the illness was detected and diagnosed, how the parents were handled by the health professionals, the parents' emotional reactions to the diagnosis and treatment and how the children reacted to the disease and treatment. Children's concepts of illness and acute loss are discussed.