Serug was the son of Reu and the father of Nahor, according to Genesis 11:20–23. He is also the great-grandfather of Abraham.
In the Masoretic text that modern Bibles are based on, he was 30 when Nahor was born, and lived another 200 years, making his age at death 230. The Septuagint (LXX) and Samaritan Pentateuch texts state that he was 130 on fathering Nahor, and the Samaritan gives his age at death as 230, stating he lived another 100 years, while the LXX has 200, making him 330 at his death.
He is called Saruch in the Greek version of Luke 3:35.
Further details are provided in Jubilees, where it gives the names of his mother, Ora (11:1), and wife Milcah (11:6). It also states that his original name was Seroh, but that it was changed to Serug in the time when Noah's children began to fight wars, and the city of Ur Kesdim was built, where Serug lived. It says this Serug was the first of the patriarchal line to abandon monotheism and turn to idol worship, teaching sorcery to his son Nahor.