Background: Oral motor stimulation interventions improve oral feeding readiness and earlier full oral feeding in preterm neonates. However, using a structured method may improve the transition time to full oral feeds and feeding efficiency with respect to weight gain and exclusive breastfeeding when compared to an unstructured intervention. Aim: To evaluate the effect of structured and unstructured oromotor stimulation program on feeding outcomes in preterm infants. Methods: A single-blind randomized controlled trial design was utilized on a purposive sample of 60 preterm infants in Neonatal Intensive Care Units at El Manial (Kaser Al Aini) that are affiliated to Cairo University from June 2023 to June 2024. The sample was simply randomly assigned to two equal groups, namely PIOMI (structured) group and sham (unstructured) group. Tools: Four tools were used for data collection, Preterm infants’ characteristics and medical history sheet, Physiologic indicators record, Feeding Outcomes record and Premature Oral Feeding Readiness Assessment Scale (POFRAS). Preterm infants who were randomized to the PIOMI group were administered five minutes oromotor stimulation before the gavage feeding three times daily for seven consecutive days. Results: Before intervention, there was no statistical significance difference between both groups baseline characteristics. The length of hospital stay does not significantly differ in both groups. Regarding physiological indicators, a statistically significant difference was detected between the two groups in their mean average of respiratory rate only. The mean weight was increased significantly in PIOMI than sham group at discharge, also, mean milk volume increased significantly at the six and seven days of intervention. Transition time to start suck from bottle and reach full oral feed were significantly earlier in PIOMI group. POFRAS mean score was increased significantly in PIOMI compared to Sham group after intervention. Conclusion: Preterm infants’ group who received 5-minute structured (PIOMI) three times daily for seven consecutive days showed higher weight gain, milk volume, POFRAS mean score and faster oral feeding transition time than unstructured (sham) group. Recommendation: based on the current study findings the researchers recommend PIOMI to be more effective for improved oral feeding in preterm infants. However, multicentric trials with larger sample sizes would be necessary to further strengthen the recommendation.