The interest in effective human resource management has increased dramatically as mean age of the workforce has been growing in the developed western countries. A part of this workforce is constituted for by knowledge intensive workers, in which the motivation dif-fers from other groups of workers. Moreover, existing literature on lifespan development research on motivation fails to differentiate sufficiently between types of worker groups; in a like manner literature on motivation of knowledge intensive workers has neglected to in-clude age differences. This results in a shortage of research of how motivation of knowledge intensive workers differs in regards to their age. The purpose of this thesis is to describe how the intrinsic motivational factors autonomy, variety in tasks, learning new things, receiving positive feedback, and the feeling of accom-plishment and value creation influence knowledge intensive workers differently in regards to their age. The thesis’ research method was qualitative and the primary empirical data was collected through a case study in which interviews with IT consultants of two different age groups were conducted. The findings revealed that differences between the age groups are present. The most ap-parent differences lie in preference for autonomy, learning new things and receiving posi-tive feedback. Variety in tasks and the feeling of accomplishment and creating value also displayed age related discrepancies between the groups.