Caffeine is commonly used in the treatment of apnea of prematurity. The skin of preterm infants varies considerably in its level of maturity. To understand skin absorption in low birthweight infants (less than 1500 gm) with gestational age between 26 and 34 weeks, a group of 56 preterm babies was studied after percutaneous application of 7.5 mg twice daily of caffeine for babies with birthweight less than 1000 gm and 10 mg twice daily for babies with birthweight more than 1000 gm. The reported technique is a useful alternative method of drug administration in premature babies. This study indicates an inverse relationship between gestational age and skin absorption contributing to a better understanding of skin barrier function in the newborn.