We know that Nob, Bob's fellow servant at the Prancing Pony, was a Bree-hobbit, but Bob's own heritage is never explicitly stated. Working in Bree, where Men and Hobbits lived side by side, he might conceivably have belonged to either of those peoples.

In the early drafts of the The Lord of the Rings, Bob was certainly a Hobbit, but so was the innkeeper of the Prancing Pony (variously named as Timothy Titus or Barnabus Butterbur in those early texts) so this is not conclusive. From his association with the Hobbit Nob, we might take it that Bob was intended to remain a Hobbit in the published book, but the two are never said to be related. In summary, it seems most natural to imagine Bob as a Hobbit, but it is not impossible that he was a actually one of the Bree-men.

In modern usage, 'Bob' is short for 'Robert', and indeed in earlier versions of the text Bob's name alternates with 'Rob', so a similar connection seems to be intended. The name Robert derives from Germanic words meaning 'fame bright'.