INTRODUCTION: The study aimed to verify the influence of oral stimulation on the evolution of the suction pattern and the conditions of the breast-feeding in 2 groups of preterm newborn infants (PTNI), based on whether they received the stimulus of non-nutritious suction (i.e., G1) or or facial sensory motor stimulation (i.e., G2). The research took place in the intensive care unit of the Santa Casa de Porto Alegre (Porto Alegre, Brazil). METHOD: This is a randomized clinical trial, which was performed from January 2012 to May 2013. It included 21 PTNIs whose gestational age ranged from 30 weeks to 36 weeks. They were clinically stable and had not serious pathologies. All PTNIs were evaluated through a protocol that assessed the readiness of the preterm infant for oral feeding (Fujinaga 2005). The randomization divided the PTNIs between the G1 group and the G2 group. Both groups received a stimulus once daily for 10 consecutive days, which was accomplished by a trained researcher. At the end of the stimulation, the protocol was reapplied. RESULTS: The total score in the protocol increased in 100% of the PTNIs, compared to the first evaluation. The average increase in the total score was from 12.7 for the G1 group and 13.5 in the G2 group. At discharge from the hospital, 4 (19%) PTNIs left with exclusive breastfeeding and 17 (81%) PTNIs left with medical indication for the use of a complement and breastfeeding. Of the 4 PTNIs with exclusive breastfeeding, 2 infants received non-nutritious suction NNS and 2 infants received OSMS. CONCLUSION: The application of an oral stimulus, independent of the technique administered, showed a beneficial effect in the evolution of the suction pattern in the PTNIs.