The paper investigates determinants of formal and non-formal continuous vocational training and its income effects among German self-employed and employed workers in 1991/92. Participation in continuous formal training is more frequently observed with employed workers, whereas self-employed are engaged more often in non-formal types of training. Estimated effects on income are rather small or equal to zero with the self-employed and rather high among employed workers, both in the group of trainees and non-trainees. Non-formal training has a non-zero effect on income as well. The determinants of income differ significantly between both groups, whether workers participate in training or not. The study concludes that the income differentials for employed workers indicate selection for promotion. Participation in training seems to be a consequence of such selection processes and not its cause.