The purpose of this study was to empirically investigate the relationship between psychological need satisfaction and intrinsic motivation as proposed by self-determination theory. Three competing hypotheses regarding the relations between need satisfaction and intrinsic motivation were tested: additive, synergistic, and balance. Two cross-sectional studies involving 1,254 employees from a broad range of Norwegian service organizations partly supported the first two hypotheses. Although the relationship between satisfaction of the needs for autonomy and relatedness with intrinsic motivation were significant, the one with satisfaction of the need for competence was not. Instead, competence was only related to intrinsic motivation when autonomy was high. Implications for practice and future research are discussed.