Omphalopagus twins are a classification of conjoined twins. They are one of the most common types of conjoined twins, representing about one-third of conjoined twins. Conjoined twins are classified by the location of their connection. In the case of omphalopagus twins, they are connected at the abdominal region. These individuals share an anterior connection of the trunk, usually at the abdomen, but the connection can range from the thorax down to the umbilicus. Usually, omphalopagus face each other.
There are four arms, four legs, and two pelvises. Omphalopagus twins may share a liver, gastrointestinal or genitourinary functions.