Promaru duties in the labor contract relationship are furnisshung labor and remuneration thereof. As the information-oriented age begins, however, the value of information as property increases so that obligation of good faith and care in the labor contract relationshio becomes significant. It is because the possibility that the related problems would oceur frequently is increased due to headhunting, etc, even in traditional business areas such as the manufaturing industry, as the idea of long-term employment system breaks and fluidity of workers expands. This obligation of good faith and care is discussed in the field of labor law as duty of loyalty, but it seems no exaggeration to say that discussion on duty of loyalty in academic circles on labor law in Korea is still in an early stage. It is very urgent, in my opinion, to develop original legal principles in he labor law, for the labor contract relationship is a continuous boligation relationship and needed to found on clioser human trust than in any other legal relationship. It is observable that laws, precedents and theories about the accessory duties of workers included in the concept of duty of loyalty has been accumulated quite fully and [ersistently in Germany. Especially in the case of Wettbenerbsuerbot, the refrainment from compeyitive acticities, regulations for maximum limit of refrainment period and payment of compensation, etc, are provided considering the negative asperct that the refrainment may freedom of occupation of workers, and detaled related regulations are provided so that it is rare in practice to conclude a contract of refrainment from competitive activitise including more than rules of law. Considering that the duty of loyalty is a very fluid idea in Korea, it seems that legal improvement concerning the problem is needed.