In order to explain the diverging well-being outcomes of workaholism, this study aimed to examine the motivational orientations that may fuel the two main components of workaholism (i.e. working excessively and working compulsively). Drawings on Self-Determination Theory, both autonomous and controlled motivation were suggested to drive excessive work, which therefore was expected to relate positively to both well-being (i.e. vigor) and ill-health (i.e. exhaustion). Compulsive work, in contrast, was hypothesised to originate exclusively out of controlled motivation and therefore to only associate positively with ill-being. Structural equation modeling in a heterogeneous sample of Belgian white-collar workers (N = 370) confirmed that autonomous motivation associated positively with excessive work, which then related positively to vigor. Controlled motivation correlated positively with compulsive work, which therefore related positively with exhaustion. The hypothesised path from controlled motivation to exhaustion through excessive work was not corroborated. In general, the findings suggest that primarily compulsive work yields associations with ill-being, since it may stem from a qualitatively inferior type of motivation.