Newly diagnosed children with leukemia and their families were subjects of a longitudinal study to describe coping behaviors, to determine adequacy of coping, and to discover predictors of healthy coping with leukemia. Families were followed for six months during which time they were interviewed, completed tests and scales, and were rated by physicians, nurses, and psychosocial staff. Families showed a wide variety of reactions and coping behaviors. The data supported the hypothesis that most families cope well despite the stresses of the first six months post-diagnosis. Based on physicians' ratings, psychosocial intervention appeared to be effective for mothers during the early outpatient phase of treatment. Age of child, previous coping, coping of other family members, a good support system, and lack of additional stresses were significantly correlated with healthy coping. The need for longitudinal assessment of coping was stressed.