Many hospitals wish to improve their patients' experience of care. To learn whether social media could be used as a tool to engage patients and to identify opportunities for hospital quality improvement (QI), we solicited patients' narrative feedback on the Baystate Medical Center Facebook page during a 3-week period in 2014. Two investigators used directed qualitative content analysis to code comments and descriptive statistics to assess the frequency of selected codes and themes. We identified common themes, including: (1) comments about staff (17/37 respondents, 45.9%); (2) comments about specific departments (22/37, 59.5%); (3) comments on technical aspects of care, including perceived errors and inattention to pain control (9/37, 24.3%); and (4) comments describing the hospital physical plant, parking, and amenities (9/37, 24.3%). A small number (n = 3) of patients repeatedly responded, accounting for 30% (45/148) of narratives. Although patient feedback on social media could help to drive hospital QI efforts, any potential benefits must be weighed against the reputational risks, the lack of representativeness among respondents, and the volume of responses needed to identify areas of improvement.