The increasing elderly population has created an urgent need for well-managed convalescent hospitals, which should provide appropriate clinical nutrition services. The new accreditation policy requiring participation of all convalescent hospitals since 2013 may promote improvement of clinical nutrition services. This study examined whether or not the accreditation policy has increased practice level and dietitians' perception of the importance of clinical nutrition management. Of the 177 convalescent hospitals accredited by January 30, 2014, dietitians from 73 hospitals (41.2%) completed the survey questionnaire. The pre-tested questionnaire surveyed general characteristics of the hospital and dietitians, current status of clinical nutrition management, and changes in the perception and practice levels of various aspects of food and clinical nutrition management. In average, dietitians with more than 5 years of work experience (68.1%) provided food and clinical nutrition services (71.2%). After accreditation, dietitians' perception of the importance and practice level of clinical nutrition service increased (P<0.001). Level of perception, however, was significantly (P<0.001) higher than practice level before and after accreditation. During perception and practice level of initial nutrition assessment, a compulsory accreditation item, notably and significantly (P<0.001) improved after accreditation. The significant difference between perception and practice level disappeared after accreditation. In conclusion, the accreditation process had positive effects on clinical nutrition management in terms of dietitians' perception and practice levels. Making more accreditation items compulsory and providing motivation and professional education to dietitians in convalescent hospitals could lead to additional improvements.