Background Balloon dilatation of the lower esophageal sphincter (LES) is one of the effective nonsurgical treatment options in the management of achalasia. We aimed to determine the long-term results of graded balloon dilatation and the factors predicting outcome. Patients Patients followed for more than 12 months between January 1995 to March 2005, without history of endoscopic or surgical therapy before the study, were included (n = 111, mean age 46.3 +/- A 16.9 years; follow-up period 46.3 [12-150] months). Patients were evaluated by barium swallow contrast studies, upper endoscopy, and esophageal manometry. Pneumatic dilatation was performed with the use of polyethylene balloon system. Patient outcome was evaluated according to manometric studies and Van Trappen staging as determined following face-to-face interviews with the patients. Results We determined clinical response rates of 98%, 85.7%, and 75% at months 24, 48, and 60. According to receiver-operating characteristics (ROC) analysis, age a parts per thousand currency sign37.5 years, LES pressure (LESP) a parts per thousand yen30.5 mmHg, LESP after first balloon dilatation a parts per thousand yen17.5 mmHg, and balloon number > 2 were found to negatively affect treatment response. Young age and higher esophageal body pressure at admission were determined to be negative predictive factors (P = 0.038, relative risk (RR) 2.6, 95% confidence interval [CI] 1.05-6.4 and P = 0.05, RR 1.069, 95% CI 0.99-1.14, respectively). Conclusion Balloon dilatation is an effective treatment of achalasia. Young age, higher esophageal body pressure, and high LESP after first balloon dilatation are negative predictive factors. Patients with young age requiring more than two balloon dilatations are likely to be unresponsive to the treatment.