Background: Gavage feeding is a common method of feeding preterm infants due to their immature sucking reflex. Gavage feeding performed on preterm infants in different ways, including continuous and intermittent bolus gavage, by using force of gravity or injection with a syringe Aim: evaluate the effect of nurses' performance regarding gravity gavage and injection force ways on gastric residual volume. Design: A quasi-experimental design. Settings: The study was conducted in the NICU department at Benha University Hospital, Benha Teaching Hospital and Specialized Pediatric Hospital. Subjects: A convenient sample of 100 nurses and purposive sample of 60 preterm infants. Tools I: A structured Interviewing questionnaire sheet consisted of 4 parts: Part 1, personal characteristics of nurses. Part 2, preterm infants' characteristics. Part 3, feeding assessment sheet. Part 4, nurses' knowledge regarding gavage feeding in preterm infants. Tools II: An observation checklists sheet Tool III: Assessment sheet for gastric residual aspiration. Results: More than half of the studied nurses had an incompetent level of practice, and (52.0%) of them had a good level of knowledge with highly statistically significant difference. Conclusion: there was a highly statistically significant positive correlation between nurses' performance regarding gavage feeding by injection force way and gastric residual volume. While there was negative correlation between gavage feeding by gravity way and gastric residual volume.  Recommendations: Implementation of training programs for nurses regarding gavage feeding methods and their effect on gastric residual.