Base on KATZ's² concepts, the authors developed an instrument to evaluate nurses' professional achievement. This instrument consists of three parts measuring respectively. The ability to conceptualize, to express humaneness and technical skills. Conceps about nurse's desirable qualities and mathematic calculations used to measure and score them are defined and described. The present study is justified by the need of awakening Nursing Services Administradors' awareness of the significance of professional evaluation's problems, considering that the quality of assistance delivered to clients can be predicted through, achievement quality measurement. The present instrument is based, not only in good nurses achievement, but also on their activities and kind of abilities they display during the efficient performance of their work. Ability, here, is considered as skills which can be developped and demonstrated through functions fulfillment