A plant for building tires includes a system for managing initial components; a system for managing the manufacturing of semi-finished products starting from one or more initial components; a system for managing the building of a green tire starting from one or more semi-finished products; and a system for managing the curing of said green tire. The logical set of a control unit for the plant and/or of one or more from among control units for the management systems and/or of an automatic visual control system is programmed for controlling at least two parameters, assigning to each of these a quality index, discarding a tire being processed when a quality index corresponding to said discard level is assigned to at least one of said parameters and feedbacking the control result of at least one parameter in order to verify the quality index of the parameters.