Background: Patient–physician communication and textual health information are central to health care. Yet, how well patients understand their physicians and written materials is under-studied. Objectives: Focusing on outpatient health care in Germany, the aim of this research was to assess patients’ levels of understanding oral and written health information and to identify associations with socioeconomic variables. Methods: This analysis drew on a 2017 health survey (n=6,105 adults 18 years of age and above). Measures for the quality of patient–physician communication were derived from the Ask Me 3 program questions for consultations with general practitioners (GPs) and specialists (SPs), and for textual health information via a question on the comprehensibility of written materials. Correlations with socioeconomic variables were explored using bivariate and multivariable logistic regression analyses. Results: Over 90% of all respondents reported that they had understood the GP’s and SP’s explanations. A lack of understanding was most notably correlated with patients’ selfreported very poor health (odds ratio [OR]: 5.19; 95% confidence interval [CI]: 2.23–12.10), current health problem (OR: 6.54, CI: 1.70–25.12) and older age (65 years and above, OR: 2.97, CI: 1.10–8.00). Fewer patients reported that they understood written materials well (86.7% for last visit at GP, 89.7% for last visit at SP). Difficulties in understanding written materials were strongly correlated with basic education (OR: 4.20, CI: 2.76–6.39) and older age (65 years and above, OR: 2.66, CI: 1.43–4.96). Conclusions: In order to increase patients’ understanding of health information and reduce inequalities among patient subgroups, meeting the communication needs of patients of older age, low educational status and with poor health is essential.