In 2011, Germany introduced a new form of drug benefit assessment, linking reimbursement prices to drug benefit and making quality of life (QoL) one of the main benefit criteria. Thus, QoL outcomes co-determine drug prices in Germany. QoL has, however, not been defined in the regulations. This study analyzed the definition and role of QoL in Germany’s drug benefit assessment. It serves as a case study on the complexity of QoL as a parameter of health technology and drug assessments, which have become mandatory in almost all industrialized countries. In a qualitative analysis, the publicly available dossiers (summaries), dossier evaluations, protocols of the oral hearings, the final resolutions of the Federal Joint Committee (G-BA) and its rationale of all benefit assessments completed by 2013 (n = 66) were processed. Additionally, quantitative data on the decision outcomes were collected. Only two decisions drew on QoL outcomes as “main justifications” for additional benefit. It was due to a lack of valid and statistically significant QoL results, a deficient presentation of QoL data, or differing understandings of QoL, that QoL benefit was not demonstrated in more than two cases. While manufacturers applied wider definitions of QoL, the assessment institutions questioned evidence if it was not reported with the help of validated QoL questionnaires or deviated from their definition of QoL. The German experience with QoL as a drug benefit criterion highlights the importance of a clear QoL definition and according methodological regulations.