Indications for cardiac resynchronization therapy (CRT) have expanded to include patients with mild congestive heart failure (CHF) symptoms (New York Heart Association [NYHA] functional class II) because of a demonstrated morbidity reduction in this subset of patients. However, little is known about postimplantation changes in their self-reported health status compared to patients with more severe CHF. The aim of this study was to examine the influence of baseline NYHA functional class on health status changes in the first 12 months after implantation of a CRT with defibrillator (CRT-D). Patients with first-time CRT-D (n = 169, 75% men, mean age 62.1 ± 10.7 years) were recruited from 3 Dutch hospitals. All patients completed the SF-36 Health Survey at the time of implantation and at 12 months after implantation. Mildly (NYHA functional class II; n = 54) and moderately (NYHA functional class III; n = 115) symptomatic CHF patients showed improved health status in several SF-36 domains at 12 months after CRT-D. When adjusting for baseline health status, the groups did not differ with respect to their health status improvement over time, but after adjustment for demographic and clinical factors, the mildly symptomatic patients reported relatively more improvement in general health (B = 10.15, SE = 3.31, p = 0.003) and social functioning (B = 10.64, SE = 3.74, p = 0.005). In conclusion, NYHA functional class II patients reported equal, and in some domains even more, improvement in health status compared to NYHA functional class III patients at 12 months after CRT-D. Hence, CRT not only prevents clinical adverse events in patients with mild CHF symptoms but also improves health status.