A large amount of professional interest has been focused upon the ambiguities and problems involved in the conduct of professional licensing and certification through examinations. What seems to be a simple problem on the surface, that being the policing of professionals for competence and the practice of conducting this policing so that it offers equal fairness to all, turns out to be a very complex problem involving unresolved conceptual, legal, and methodological issues particularly with examination validity. There are four main areas of concern: (1) criticism of testing, (2) the growing number of jobs requiring licensing, (3) discriminatory practices in hiring and occupations access, and (4) validity of certification through testing. The example used is the field of nursing. (Author/DEP)