Purpose After laparoscopic sleeve gastrectomy (LSG), several studies have reported an increase in the incidence of gastroesophageal reflux (GERD). The etiopathogenesis of GERD post-LSG is multifactorial, and hiatal hernia (HH) is one of them. The primary objective was to measure the incidence of de novo HH post-LSG. The secondary objectives were to relate the presence of HH with GERD, the chronic use of proton pump inhibitors (PPI), and the time elapsed from LSG. Materials and Methods A surgical evaluation of the crura after LSG was performed. A retrospective cohort study of 74 consecutive patients with history of LSG submitted to an intra-abdominal surgery that allowed the evaluation of the crura. Results Of a total of 74 patients, 51 were included. At the time of surgery, 37 patients (72.5%) had a HH; 24 patients (47.1%) had GERD, and 23 patients (45.1%) were frequently using PPI. When patients with HH and those without HH were compared, GERD was observed in 56.8% versus 21.4% (p = 0.01) and frequent consumption on PPI was found in 54.1% versus 21.4% (p = 0.02). According to the data of LSG, with a follow-up of < 18 months, 60% presented HH; meanwhile, with a follow-up of > 18 months, 84.6% presented HH (p = 0.02). Conclusions Patients submitted to LSG showed a high incidence of de novo HH. HH was associated with a higher incidence of GERD and PPI dependence. The longer the time elapsed from the LSG, the greater the incidence of HH.