This retrospective study compares the results of primary gastric bypass (PGB) versus secondary gastric bypass (SGB) performed after gastroplasty. Between January 2004 and August 2008, 576 consecutive patients benefited from laparoscopic gastric bypass (LGB) in our hospital. Four hundred seventy patients (81.6%) were available for full evaluation. Primary outcome measures were operative time, conversion to open surgery and mortality, hospital stay, early and late complications, reoperations, efficacy, and patient satisfaction. Three hundred sixty-two patients benefited from a PGB and 108 from SGB. Median preoperative BMI was 42 kg/m(2) (34.8-63.5; PGB) and 39 kg/m(2) (20.9-64.5; SGB; p = 0.002). Median operative time was 109 min (40-436; PGB) and 194 min (80-430; SGB; p < 0.001). There was no conversion to open surgery or mortality in either group. Median hospital stay was 4 days (3-95; PGB) and 5 days (2-114; SGB; p < 0.001). Early complications were recorded in 37 patients (10.2%) after PGB and in 24 patients (22.2%) after SGB (p < 0.001). Reoperation was necessary in 12 patients (3.3%) after PGB and in 9 patients (8.3%) after SGB (p=0.03). Median follow-up was 35 months (12-66; PGB), and 34 months (12-66; SGB; NS). Late complications were achieved in 46 patients (12.7%) after PGB and in 33 patients (30.6%) after SGB (p < 0.001). Reoperation was necessary in 17 patients (4.7%) after PGB and in 11 patients (10.2%) after SGB (p=0.03). Mean %EWL was 74.2% after PGB and 69.9% after SGB (NS). After PGB, 89% of the patients was satisfied, 4% neutral, and 6% unsatisfied; after SGB, 79% was satisfied, 10% neutral, and 11% unsatisfied (p=001). Weight loss after PGB and SGB is not statistically significantly different. Otherwise, operative time, hospital stay, complications, and revision rate are statistically significantly higher after SGB (p < 0.001).