In this study we examine the introduction of online homework in a first-semester engineering mathematics course at a German university of applied sciences. The aim of the study was to find out whether students in general and students with low incoming mathematics skills in particular benefit from graded online homework. We found a high correlation between the number of online homework problems correctly solved and exam results, but also between placement test scores and exam results. Furthermore, we found that students with high placement test scores were more likely to use online homework regularly. We conclude that although online homework can promote successful student learning, further efforts are necessary to ensure completion of homework especially by students with low placement test scores.