Competencies consist of the knowledge, skills, abilities, and other characteristics that contribute to successful job performance. The competency movement in Industrial/Organizational Psychology started in the 1970s in response to the inability of traditional aptitude, tests, to predict job performance. If traditional aptitude measures did not predict job performance, then what would? Researching characteristics of people who did a job well led to the competency framework as a model to distinguish characteristics that differentiated superior from average performance. In more recent years there has been another explosion of interest in competencies in the Human Resource (HR) environment because of the growing concern that traditional job analysis procedure are not able to effectively adapt to the new emerging HR management environment (e.g., distributed teams, complexity of work, changing work structures). The Navy also believes that a competency based approach has value and has committed to implementing a competency-based strategy for the Navy's Total Force (TF). Navy researchers are currently implementing a phased approach to develop competencies for the work of the Navy. Proficiency levels will be used to measure one's capability to demonstrate a competency (technical and non-technical) and to delineate the required competencies (technical and non-technical) for a billet. Different positions will require different levels of proficiency and competencies for successful performance. The mapping of competencies and proficiencies to the job requirements is concurrent and ongoing. This paper describes the advantages and challenges of implementing competencies and proficiencies for the Navy.