Nasogastric tubes (NGT) still remain the easiest and the best way for gastrointestinal tract access. There are various indications for the insertion of a nasogastric tube in anaesthetized and critically ill patients. Although many techniques have been introduced to facilitate nasogastric tube insertion using anatomic landmarks and a group of devices, there is no consensus on a standard method. Moreover, there are different methods for the assessment of the correct placement of a nasogastric tube. In addition to these challenges in insertion and assessment methods, there are varieties of major life-threatening and minor complications to be addressed. Thus, selecting the most appropriate approach requires enough knowledge in this area, considering patient condition and clinical factors, as well as the practitioners' sufficient education and experience, along with skill in performance. This is a comprehensive review of the literature evidence on different methods for nasogastric tube insertion, on the assessment of correct placement and the evaluation of complications, in addition to an approach to the effect of education on the quality of routine practice and patients' outcome.