Employees in a low socio-economic position (SEP) are more likely to leave the labour market after medical rehabilitation for health reasons than those in a better social position. So far, almost nothing is known about whether certain types of rehabilitative care can reduce this inequality in rehabilitation success. This paper examines whether certain types of care modify the SEP's influence on return-to-work (RTW). The study is based on administrative data from the German statutory pension insurance on 266,413 medical rehabilitations of 253,311 persons fully integrated into working life. Poisson regression analyses were used to check whether there was a correlation between SEP (income, education, occupational position) and the probability of RTW in the year following the measure, and whether this correlation was lower in follow-up treatment (AHB), inpatient treatment or treatment with subsequent graded RTW compared to rehabilitation that did not meet these characteristics. People with a low income, education or occupational position were at increased risk of incomplete return to work after medical rehabilitation. This correlation was comparatively lower for all 3 SEP indicators when the return to work was gradual. In the case of AHB and inpatient rehabilitation, this only applied to income. Socio-economically disadvantaged population groups are comparatively more likely not to return fully to work after medical rehabilitation. These inequalities are less pronounced for certain types of rehabilitative care. This tends to be the case with an active structuring role of the care system. However, there is a need for further research on the modification of effects by the type of treatment. This should be further investigated using data collected for this purpose to exclude selection effects.