An uncircumcised penis has not had the foreskin removed. Foreskin is the loose skin that covers, partially or fully, the head of a penis. All boys are born with foreskin.

An uncircumcised penis may look different from one that is circumcised, but the differences are less noticeable when the penis is erect (the foreskin pulls back to expose the head). It is important to wash under foreskin regularly in order to avoid a bad smell or an infection.