The Assyrian clay tablet, discovered by researchers including those from Harran University in Turkey, details a marriage contract between a man named Laqipum and his bride, Hatala.
It says that if Hatala is unable to have a child, she will buy a slave woman, known as a hierodule, to sleep with her husband.
"There are many different ways to solve infertility problems - like surrogacy, as mentioned even 4,000 years ago in this Assyrian clay tablet," researchers wrote in the study published in the journal Gynecological Endocrinology.
The marriage contract shows that "the concept of infertility is not just a disease of our age," but rather one of the ages, they said.
"Should Laqipum choose to divorce her, he must pay (her) five minas of silver - and should Hatala choose to divorce him, she must pay (him) five minas of silver," according to a translation of the contract.
The tablet was discovered in modern-day Turkey at Kultepe-Kanesh, an archaeological site on the World Heritage list kept by the United Nations Educational, Scientific and Cultural Organization (UNESCO).