Enlargement of perivascular spaces has been associated with a number of diseases. However, morphological features of perivascular spaces in healthy subjects and their clinical role are still not completely understood. We analyzed on MRI perivascular spaces in a large sample of healthy young subjects. Our results showed a high inter-subjects variability of perivascular spaces. Twins presented similar amount of perivascular spaces. Perivascular spaces in basal ganglia were significantly correlated with subjects’ height, brain volume, and brainstem volume. These findings are relevant for all future studies investigating the role of perivascular spaces.