Sixty-nine (13M, 56F), severely obese patients (body mass index 47 kg/m2) have had vertical banded gastroplasty (GP) with 5-cm polypropylene mesh (n = 39) or fascia (n = 30) bands since 1981. Of these 69 patients, 30 also had truncal vagotomy (TVG) without drainage. Total office follow-up rate is 94%. During follow-up of 1 year or more (mean 60 months), 25 patients with vagotomy plus gastroplasty lost 33 +/- 3 kg, corresponding to 51% of excess weight, compared to 21 +/- 3 kg (34% excess weight) in the 34 patients having gastroplasty alone (p < 0.01). In patients followed greater-than-or-equal-to 5 years (mean 83 months) 10 patients with TVG lost 40 +/- 5 kg (61% of excess) compared to 17 +/- 4 kg (28% of excess) in 22 patients with GP alone (p < 0.001). Frequency and severity of complications were similar in both groups, but there were seven reoperations after GP and three after TVG (p < 0.05). Studies of gastric emptying of a solid meal in 14 of the patients with GP and 14 with TVG demonstrated greater weight loss in those with prolonged emptying and gastroesophageal pooling, though the emptying rates of patients with GP and those with TVG showed no statistically significant difference. Our earlier studies, which showed reduced liquid consumption after vagotomy, imply that this mechanism (rather than delayed emptying) explains why vagotomy potentiates weight loss after gastroplasty.