To identify supervisory factors related to job satisfaction among certified nursing assistants (CNAs). Although this topic has been studied at the facility and state levels, it has not previously been addressed in a nationally representative sample. Cross-sectional analysis of data from the 2004 National Nursing Assistant Survey, conducted by the National Center for Health Statistics. Nationally representative sample of nursing homes (n = 790). Eight randomly selected CNAs from each nursing home, 4 who had been at that job for less than 1 year and 4 at the job for a year or more (n = 3011). Analysis was limited to 2897 individuals working at the same facility when interviewed. Job satisfaction was measured by a 6-item score addressing workplace morale, challenging work, benefits, salary or wages, learning new skills, and overall satisfaction. Characteristics of the work environment included supervisor behavior, time pressures, organizational climate, perception that the CNA's work was valued, and whether the CNA principally cared for the same residents. In adjusted analysis, organizational climate, supervisor behavior, sufficient time for tasks, and being valued were positively associated with job satisfaction, as were hourly earnings. Clear communication from supervisors and evidence that the CNA function is valued were associated with job satisfaction. Specific strategies, such as merit raises and job design, may increase job satisfaction. Copyright (c) 2010 American Medical Directors Association. Published by Elsevier Inc. All rights reserved.