In the article titled “Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel” [1], there is a systematic error in the yields reported (in g/g) in section “3.1.1. Activated Sludge.” It is reported again in section “4. Conclusions.” These yields need to be divided by a factor of 10, due to a conversion mistake. This does not alter or affect the discussions and conclusions that have been reached in this paper, since the scope was to make a comparison among the different mixed cultures obtained.