This paper used Leader Member Exchange Theory (LMX) as a lens for comparing the impact of the supervisor-subordinate relationship on two types of professionals' perceptions of autonomy and in turn, upon their affective commitment. The reason for examining autonomy is because a characteristic of being a professional is having autonomy; however, we argued that such perceptions are affected by the quality of the supervisor-subordinate relationship. The findings confirmed this argument, although the trend was stronger for engineers compared with nurses. Using the OLS procedure, the goodness of fit of the model identified that supervision and autonomy accounted for approximately a third of the variance of engineers' levels of affective commitment and a fifth of the variance for nurses. That is, the impact of supervision practices was stronger on autonomy and commitment for engineers than for nurses in Australia. Moreover, statistically, the two groups of professionals were similar in their perceptions of the quality of their supervisor-subordinate relationship as well as their perceptions of autonomy, and the qualitative findings supported similar factors impacting upon their perceptions. The only significant difference between the two groups was in their levels of affective commitment. The implications of these results include the need for those managing professionals to consider ways of improving workplace supervisor-subordinate relationships because of the impact upon perceived autonomy as well as commitment to their organisation, and hence the retention of such professionals.