Exocrine pancreatic insufficiency (EPI) is a common problem after surgery of the pancreas and stomach. It is usually caused by inadequate pancreatic enzyme activity resulting from insufficient enzyme production, insufficient enzyme activation or disturbed enzyme deactivation. A variety of direct and indirect pancreatic function tests such as the secretin-cerulein test, the faecal elastase test and the (13)C-mixed triglyceride breath test are used to assess exocrine pancreatic function. Few studies have addressed pancreatic enzyme replacement therapy (PERT) following pancreatic surgery. These studies suggest beneficial effects of enzyme replacement after pancreatic resections. A number of studies have been performed to assess post-gastrectomy maldigestion and PERT. The treatment options remain controversial, although the published evidence is in favour of PERT leading to an overall improvement of symptoms. In conclusion, EPI following pancreatic surgery and total or partial gastrectomy remains a common clinical challenge. As a result of the lack of solid evidence, more clinical trials, particularly randomized, controlled clinical trials, are urgently needed.