Abstract: To monitor the pressing forces of an upper and lower piston of a tablet press which cooperate as a piston pair, in the currently-known process an average value formed from successive pressing force measurement results is compared with two adjustable tolerance bounds and that average value is correlated with two adjustable individual value limits which follow the course of this average value or are fixed. Maxima of individual pressing force measurements are compared with these individual value limits. To detect certain operational difficulties involving slight damage to an individual piston while avoiding tolerance ranges which are so narrow that frequent stopping of the press occurs piston pair average value limits, with which the piston pair average value of the pressing force is compared, are associated with the individual piston pairs. These piston pair average values are stored in a controlling computer which can stop the tablet press and indicate a faulty piston.