There is described a labelling machine (1) for applying a plurality of labels (2) to a respective plurality of articles (3); the machine (1) comprises a conveying device (7) movable along a given path (P) and having a plurality of operating units (15) for receiving and retaining the articles (3) to be labelled, feeding means (10) for feeding the labels (2) to the operating units (15), application means for applying the labels (2) to the articles (3), and a marking unit (100) arranged upstream from the conveying device (7) and comprising means (101) for marking a surface of each label (2) with a mark (M) univocally associable with the corresponding operating unit (15) by which said label (2) shall be received and processed.