Background: Quality of life (QOL) is impaired in functional dyspepsia (FD). Little is known about the effects of different therapies on the QOL profile in patients with this condition. Objectives: The aims of this study were to measure baseline QOL in patients with FD and to assess changes in QOL over time associated with Helicobacter pylori eradication and prokinetic treatment. The primary and secondary end points were the improvement in QOL 6 weeks and 1 year after successful eradication of the infection or prokinetic therapy. Methods: This 1-year, single-center, prospective, open-label, controlled, parallel-group trial was conducted at the Department of Gastroenterology, Ferencvdros Health Centre, Budapest, Hungary. The Functional Digestive Disorder Quality of Life (FDDQoL) Questionnaire (MAPI Research Institute, Lyon, France) was translated and validated previously in Hungarian. Male and female subjects aged 20 to 60 years were enrolled and classified as H pylori positive (HP+), H pylori negative (HP-) with FD, or healthy (control group). The HP+ patients received pantoprazole 40 mg BID + amoxicillin 1000 mg BID + clarithromycin 500 mg BID for 7 days, followed by on-demand ranitidine (150–300 mg/d) for 1 year. The HP- patients received the prokinetic cisapride 10 mg TID for 1 month, followed by on-demand cisapride (10–20 mg/d) for 1 year. The FDDQoL questionnaire was completed by all 3 groups on enrollment, at 6 weeks, and 1 year. Results: A total of 101 HP+ patients, 98 HP- patients, and 123 healthy controls were included in the study (185 women, 137 men; mean age, 39.0 ears). The mean (SD) baseline QOL scores were significantly lower in the HP+ group (53.3 [9.6]; 95% CI, 54.4-58.2) and the HP- groups (50.0 [9.8]; 95% CI, 58.0–62.0) compared with that in healthy controls (76.2 [8.7]; 95% CI, 74.6–77.8) (both, P < 0.001). Analysis of the short-term domain scores found that the HP+ group had significantly decreased scores in 6 of 8 domains: daily activities ( P = 0.005), anxiety level ( P = 0.02), diet ( P = 0.008), sleep ( P < 0.001), discomfort ( P = 0.004), and disease control ( P = 0.02); the HP- group had significantly decreased scores in 5 of 8 domains: daily activities ( P < 0.001), diet ( P = 0.004), sleep ( P = 0.005), discomfort ( P < 0.001), and disease control ( P = 0.02). Eradication of the infection was successful in 77/101 (76.2%) of the patients on intent-to-treat analysis and 77/94 (81.9%) on per-protocol analysis. Eradication was associated with an increase in mean (SD) QOL score to 70.8 (10.7) at 6 weeks (95% CI, 63.3–73.2; P < 0.001 vs baseline) and to 75.3 (9.3) at 1 year (95% CI, 73.2–77.5; P= 0.05 vs 6 weeks). In the HP- group, the QOL score increased to 73.3 (9.7) (95% CI, 71.3–75.4; P < 0.001 vs baseline) at 6 weeks of cisapride treatment and to 76.5 (8.5) at 1 year (95% CI, 74.5–78.4; P = 0.06 vs 6 weeks). Most of the impaired domain scores improved significantly after both treatments. The short-term effect size was 1.48 in HP+ and 1.35 in HP− patients. Adverse events (AEs) occurred in 22 (21.8%) patients in the HP+ group (nausea, 8 [7.9%] patients; diarrhea, 5 [5.0%]; loss of appetite, 5 [5.0%]; stomatitis, 5 [5.0%]; abdominal pain, 4 [4.0%]; bloating, 4 [4.0%]; headache, 4 [4.0%]; vomiting, 4 [4.0%]; constipation, 3 [3.0%]; and vaginitis, 3 [3.0%]). In HP− cases, AEs occurred in 9 (9.2%) patients (abdominal cramps, 7 [7.1%]; diarrhea, 4 [4.1%]; and nausea, 3 [3.1%]). Conclusion: In this study in patients with FD and healthy controls, eradication of H pylori infection in infected patients and cisapride treatment in uninfected patients reversed low QOL scores during the 1-year follow-up period.