Objectives: Feeding problems can occur in early-term infants born at 37 weeks. Early-term and full-term infants may benefit from oral motor therapy to attain successful breastfeeding. The present study aims to determine the impact of the 5-minute premature infant oral motor intervention (PIOMI) and the 15-minute oral stimulation program (15-minute oral stimulation program) on 37 to 41 weeks infants in attaining successful breastfeeding. Methods: This clinical trial was conducted on early-term and full-term infants in the neonatal intensive care units (NICUs) of two hospitals in Mashhad City, Iran. They were randomly divided into two intervention groups (5-minute PIOMI or 15-minute oral stimulation program) and one control group (17 infants in each group). These three groups were then compared to each other after the intervention by pediatricians and speech and language specialists regarding their breastfeeding. All statistical analysis was performed using R software, version 4.0.2, and the significance level was set at 0.05. Results: Infants in both intervention groups attained different levels of breastfeeding compared to pre-intervention. This outcome could be due to our interventions or natural growth and development (P<0.05). However, the longer the infants’ oral motor therapy time was, the more likely they were to breastfeed successfully. The 15-minute oral stimulation program group had a significantly higher number of male infants attaining breastfeeding after treatment than the control and PIOMI groups (P=0.03). Discussion: The PIOMI has been confirmed as an effective early intervention for small preterm infants as young as 29 weeks, and the short 5-minute therapy time is accepted in the preterm infant population. The program affects the brain’s plasticity and improves neurosensory and motor skill development for feeding. The current study indicates that PIOMI remains effective versus the control group in the full-term babies. However, the longer 15-minute oral stimulation program, is more effective in full-term infants. This finding shows that full-term infants can endure and benefit from longer than 5 minutes per day of oral motor therapy.