OBJECTIVE : Given the increase in the birth and survival rate of the premature infants, a need for supportive health care services becomes more evident. The goal of the present study was to examine the effectiveness of the Premature Infant Oral Motor Intervention (PIOMI) in the feeding progression and early intervention. This study was a double-blind randomized clinical trial. METHODS : This clinical trial included premature infants in the neonatal intensive care units (NICUs) of two hospitals in Tehran, who were randomly assigned into intervention and control group, each containing 15 infants. The PIOMI was administered to the intervention group in the course of 10 days. The infants in the control group received routine nursing services. Repeated measures ANOVA (RMA) were analyzed. The postmenstrual age and weight of the participants were examined at the time points of accomplishing one, four, and eight oral feedings a day and at the time of hospital discharge. RESULTS : The intervention group reached the first oral feeding (with a mean of 7.2 days) and eight oral feeding (with a mean of 13.47 days) earlier than the control group. The length of hospital stay in intervention group was significantly shorter (P = 0.03). RMA wasn't statistically significant between groups for weight (F: 0.76, P: 0.39, ŋ: 0.03); but within-subjects test showed that change of the weight over time and for interaction of time and group was significant (F: 74.437, P < 0.001, ŋ: 0.727). The effect size of infants' age in the measurement times was 91%. CONCLUSIONS : the results revealed that PIOMI is a fruitful method for premature infants. We suggest that PIOMI can be integrated in feeding rehabilitation programs of the premature infants born with gestational age of as young as 26-29 weeks, and applied at 29 weeks postmenstrual age (PMA). UNASSIGNED : IRCT20180410039260N1.