The ABC analysis is an often used tool for distinguishing phenomena when so
lving tasks related to production planning and control. The ABC analysis re
presents the basic tool for introducing the Just in Time supply and product
ion as well as production segmenting. Experiments have proven the inaccurac
y of the classic method of dividing a set of phenomena Minto subsets A, B a
nd C. Therefore, a method which would improve the accuracy has been searche
d for. To improve the accuracy of dividing phenomena into subsets, the comp
uter supported three-line ABC analysis is suggested.