The relationships between work force size and multiple facets of job satisfaction were examined, using data from 2 national surveys in the United States and Canada. The number of benefits offered by an organization was tested as a possible mediator of these relationships. As predicted, work force size was positively and significantly related to satisfaction with job security, pay, and promotion opportunities in the U.S. sample. When the effect of benefits was controlled for, however, these relationships were no longer statistically significant, suggesting that benefits had a mediating effect. Work force size was negatively and directly related to satisfaction with supervisor competence and having the opportunity to do one's best. These results were replicated in a representative Canadian sample. Thus, benefits had a mediating effect on the relationship between work force size and those facets of job satisfaction over which the organization had the most control (e.g., promotion, pay). Work force size had a direct effect on those facets of job satisfaction over which the organization had less control (e.g., co-workers).