Individual differences and work-context characteristics may lead to differences in employees' motivation, job satisfaction and performance. In an era when public organizations seek to attract and retain highly qualified employees, managers and designers of motivation systems should carefully scrutinize and evaluate the reward preferences of their personnel. Using descriptive statistics and ordered probit regression models on data from a unique questionnaire-based survey, we explore how individuals' demographic characteristics and organizational work environments influence work motivation in the extended public sector of Greece. Literature on work motivation has long been focused into two major approaches: the organizational economic approach -focusing on extrinsic rewards; and the organizational behaviour approach -emphasizing intrinsic motivation. Accordingly, the motivators addressed in this study are presented in the form of extrinsic and intrinsic incentives. Our findings show that the expected work outcome of public employees is directly influenced by a multifaceted context of motivators; however extrinsic rewards seem to exert stronger influence on employees' preferences than intrinsic motives, including those related to public and altruistic service. In addition, econometric results indicate that individual characteristics comprise a more decisive set of factors in determining the motivation patterns of public employees compared to work-related influences.