Background: Knowledge about the association between frailty and self-reported health among patients undergoing heart valve surgery remains sparse. Thus, the objectives were to I) describe changes in self-reported health at different time points according to frailty status, and to II) investigate the association between frailty status at discharge and poor self-reported health four weeks after discharge among patients undergoing heart valve surgery. Methods: In a prospective cohort study, consecutive patients undergoing heart valve surgery, including transapical/transaortic valve procedures were included. Frailty was measured using the Fried score, and self-reported health using the Kansas City Cardiomyopathy Questionnaire (KCCQ) and the EuroQoL-5 Dimensions 5-Levels Health Status Questionnaire (EQ-5D-5L). To investigate the association between frailty and self-reported health, multivariable logistic regression models were used. Analyses were adjusted for sex, age, surgical risk evaluation (EuroScore) and procedure and presented as odds ratios (OR) with 95% confidence intervals (CI). Results: Frailty was assessed at discharge in 288 patients (median age 71, 69% men); 51 patients (18%) were frail. In the multivariable analyses, frailty at discharge remained significantly associated with poor self-reported health at four weeks, OR (95% CI): EQ-5D-5L Index 3.38 (1.51–7.52), VAS 2.41 (1.13–5.14), and KCCQ 2.84 (1.35–5.97). Conclusion: Frailty is present at discharge in 18% of patients undergoing heart valve surgery, and being frail is associated with poor self-reported health at four weeks of follow-up. This supports a clinical need to address the unique risk of frail patients among heart valve teams broadly, and not only to measure frailty as a marker of operative risk.