Mental rotation is a complex cognitive skill depending on the manipulation of mental representations. We aimed to investigate the maturing neuronal network for mental rotation by measuring brain activation in 20 children and 20 adults using functional magnetic resonance imaging. Our results indicate that brain activation patterns are very similar between children and adults. However, adults exhibit stronger activation in the left intraparietal sulcus compared to children. This finding suggests a shift of activation from a predominantly right parietal activation in children to a bilateral activation pattern in adults. Furthermore, adults show a deactivation of the posterior cingulate gyrus and precuneus, which is not observed in children. In conclusion, developmental changes of brain activation during mental rotation are leading to a bilateral parietal activation pattern and faster performance.