The feasibility of functional imaging of neonatal brains was studied in a noninvasive transcranial manner by using reflection mode photoacoustic technique for the first time. Experiments were conducted to examine the quality of photoacoustic signals and consequent images across a newborn infant skull. With the designed system, photoacoustic imaging of blood vessels through the infant skull has been achieved with an axial resolution up to 50mum and a lateral resolution up to 420mum. Experimental results also indicate that photoacoustic imaging of neonatal brain with a depth of 21mm or more beneath the skull is feasible when working with near-infrared light. Moreover, the performance of this technique for measuring and monitoring the changes in blood oxygenation level through the newborn infant skull has also been explored. This study suggests that reflection mode photoacoustic imaging holds promise to become a novel and powerful tool for noninvasive diagnosis, monitoring and prognosis of disorders in neonatal brains.