Hernias are among the most common long-term complications after bariatric surgery. Besides incisional hernias, which occur very often after conventional open bariatric surgery, internal hernias after bariatric surgery constitute a special challenge. The incidence of internal hernias after bariatric surgery is more common than for other upper gastrointestinal tract operations. Internal hernias are not limited to laparoscopic procedures but are also observed after conventional open gastric bypass surgery. As the incidence is significantly increased after laparoscopic interventions, there seems to be a close association with minimally invasive procedures. The clinical symptoms of internal hernias without complete obstruction are non-specific and the correct diagnosis is often not straightforward. In addition to the aspects of prevention of internal hernias in laparoscopic surgery, this article discusses the diagnosis and treatment, taking into account the various forms of internal hernia after bariatric operations.