India has one of the world's largest and most significant bodies of rock paintings and engravings, yet not a single rock art site or image has been directly and accurately dated using radiometric techniques. Here we report on results from the Billasurgam Cave complex near Kurnool in southern India. Although this cave complex has been investigated archaeologically since the late 1800s, it was not until 2008 that a large petroglyph, consisting of the remains of three nested diamond designs on a stalactite, was noted. In order to determine if this petroglyph had been made recently, flowstone was sampled from on top of and below the engraving. Radiocarbon dating revealed a mid-Holocene age of about 5000 cal BP for the petroglyph, but we cannot rule out the possibility that the engraving is several centuries younger. Similar nested diamond designs at some rock painting sites and on a chert core elsewhere in India have been assumed to be Mesolithic. Our result is consistent with this hypothesis, although we note that it also consistent with the creation of the petroglyph in the early Neolithic. We conclude that the Billasurgam engraved diamond design was probably made by Mesolithic foragers of the Kurnool region and is the oldest surviving form of rock art yet directly dated in southern India.