Persons with acute and chronic illnesses must frequently respond to a number of illness-related tasks and stressors. Changes in an individual's coping style over the course of an illness, however, are rarely studied. Most coping inventories are too long to be practical for the necessary repeated administration. A study was undertaken to develop a brief coping scale for use with children and adolescents with chronic illnesses. KIDCOPE, a brief coping checklist comprised of 10 items, was developed which covered problem-solving, distraction, social support, social withdrawal, cognitive restructuring, self-criticism, blaming others, emotional expression, wishful thinking, and resignation. Four samples of "normal" adolescents (total N=364) and one clinical sample of adolescent suicide attempters (N=25) participated in reliability and validity studies. The results revealed that the highest correlations were obtained when subjects rated the same personal stressors 3 days apart, lower correlations were obtained when ratings were 1 week apart, and lowest correlations were obtained over 10 weeks with different stressors. These findings suggest that coping is a process measure with only minimal consistency within individuals over time. Validity studies revealed moderate to high correlations between the Coping Strategies Inventory and the KIDCOPE. (NB)