This study evaluates the knowledge of nurses working in intensive care units concerning recommendations for the proper administration of medication through nasogastric and enteral tubes. This exploratory-descriptive study with a quantitative approach was carried out with 49 nurses in an intensive care unit of a tertiary hospital in Fortaleza, CE, Brazil. A total of 36.7% of nurses reported they disregard the dosage forms provided by the pharmacy at the time of administering the medication through tubes. Metal, wood, or a plastic mortar is the method most frequently reported (42.86%) for crushing prescribed solid forms; 32.65% leave the drugs in 20 ml of water until dissolved; 65.3% place the responsibility for choosing the pharmaceutical formulation and its correlation with the tube site, either into the stomach or into the intestine, on the physician. The results indicate there is a gap between specific literature on medication administered through tubes and knowledge of nurses on the subject.