BACKGROUND Laparoscopic sleeve gastrectomy (LSG) is gaining popularity as an additional bariatric procedure, either as a first step for biliopancreatic diversion or gastric bypass or as a stand-alone option for selected patients. Early postoperative fluid tolerance varies between patients and influences the length of hospital stay. Swallow studies after LSG are not uniform and display different patterns with regard to contrast passage through the gastric sleeve. METHODS The 55 patients (40 women) in this study underwent LSG during 18 months. These patients had a mean age of 38.2 years (range: 17-61 years) and a mean body mass index (BMI) of 44.8 kg/m(2) (range: 39-75 kg/m(2)). The LSG procedure was performed using a four-port technique to resect the greater curvature of the stomach around a bougie. The mean operative time was 120 min (range: 45-240 min). A routine swallow study was performed on postoperative day 1, and clear fluids were initiated if no leak was detected. Patients were discharged when they could tolerate a daily fluid intake of 2 l. RESULTS No mortalities, obstructions, or leaks occurred in the study cohort. Two main patterns of contrast passage were identified: type 1 (immediate unhindered flow through the sleeve to the antrum with a slight delay before continuation of the contrast to the duodenum) and type 2 (contrast filling of the proximal sleeve with delay of flow distally toward the duodenum). Patients with rapid contrast passage (group 1, n = 24) tolerated clear fluids better than those with delayed flow (group 2, n = 31) and were discharged earlier than their counterparts (mean length of hospital stay, 2.5 vs. 3.4 days; p < 0.001). CONCLUSIONS Tolerance of fluid intake after LSG is crucial for patient recovery and discharge. A distinct radiologic appearance on postoperative day 1 helps to predict this behavior. The different patterns could be related to gastric sleeve construction or to possible postoperative sleeve spasm, hindering fluid passage. The influence of immediate fluid tolerance on weight loss after LSG is currently under investigation.