The APPLE study is a multicenter, clinical study aimed at pediatric patients with pancreatitis. The study protocol is suitable for tracking both newly diagnosed (APPLE-P, prospective study) and earlier episodes (APPLE-R, retrospective study) of pancreatitis. There is little information available on pediatric pancreatitis. The incidence of pediatric pancreatitis has increased in the last 10 years. According to our current knowledge, the occurance of genetic risk factors in pediatric pancreatitis could be significantly, even 10 times higher, than in adults. Also, we know that the role of alcohol is insignificant in etiology. Children having acute pancreatitis are probably going to have recurrent episodes, that eventually may lead to chronic pancreatitis. Except etiology, we have little information on the development of the disease and its effect on life quality.