Background: Stimulating preterm neonates with breast milk odor is a useful strategy for enhancing the physiological, and behavioral responses and feeding progression of preterm neonates. Aim: The study aimed to assess the effect of breast milk olfactory stimulation on behavioral responses and feeding progression of preterm neonates Settings: The study was conducted in the Neonatal Intensive Care Unit (NICU) at Alexandria University Children's Hospital at Smouha Subjects: A convenient sample of 60 preterm neonates who admitted to the previously mentioned setting. The neonates were randomly assigned into two equal groups, study, and control (30 neonates for each). The preterm neonates of the control group received routine care in the unit. Whereas the preterm neonates of the study group received breast milk olfactory stimulation. Tools Three tools were used to collect data. Characteristics and physiological parameters of Preterm Neonates Assessment Record, Neonatal Behaviors Assessment Record, and Preterm Neonates Feeding Progression Assessment Record Results: There were statistically significant differences found between both groups according to the weight of preterm neonates on the first, third, and seventh days (p=<0.001 for each). Further statistically significant differences were found regarding to mean amount of milk between both groups on the third and seventh days (p=<0.005 & p=<0.001 respectively).Conclusion: Preterm neonates who received olfactory stimulation exhibited better-organized behaviors than preterm neonates who did not. Moreover, the preterm neonates who received breast milk olfactory stimulation also had feeding progression (weight gain and amount of milk received daily) more than preterm neonates in the control group. Recommendation: Neonatal Intensive Care Nurses should be trained in the application of olfactory stimulation for preterm neonates. Various types of sensory stimulation should be integrated into NICU routine care for preterm neonates