Chronica, to which Catullus seems to allude in his dedication to Nepos. Ausonius also mentions it in his sixteenth Epistle to Probus, as does Aulus Gellius in the Noctes Atticae (XVII.21). It is thought to have been written in three books.

Exemplorum libri, of which Charisius cites the second book, and Aulus Gellius the fifth (VII.18).

De Viris Illustribus, from which Aulus Gellius draws an anecdote of Cato (IX.8).

De Vita Ciceronis. Aulus Gellius corrects an error in this work (XV.28).

Epistulae ad Ciceronem, an extract of which survives in Lactantius (Divinarum Institutionum Libri Septem III.15). It is unclear whether they were ever formally published.

Pliny the Younger mentions verse written by Nepos, and in his own Life of Dion, Nepos himself refers to a work of his own authorship, De Historicis. He also mentions a longer Life of Cato at the end of the extant Life of Cato, written at the request of Titus Pomponius Atticus.

His only surviving work is the Excellentium Imperatorum Vitae, which appeared in the reign of Theodosius I, as the work of the grammarian Aemilius Probus, who presented it to the emperor with a dedication in Latin verse. He claims it to have been the work of his mother or father (the manuscripts vary) and his grandfather. Despite the obvious questions (such as why is the preface addressed to someone named Atticus when the work was supposedly dedicated to Theodosius), no one seemed to have doubted Probus's authorship. Eventually Peter Cornerus discovered in a manuscript of Cicero's letters the biographies of Cato and Atticus. He added them to the other existing biographies, despite the fact that the writer speaks of himself as a contemporary and friend of Atticus, and that the manuscript bore the heading E libro posteriore Cornelii Nepotis ('from the last book of Cornelius Nepos') At last Dionysius Lambinus's edition of 1569 bore a commentary demonstrating on stylistic grounds that the work must have been of Nepos alone, and not Aemilius Probus. This view has been tempered by more recent scholarship, which agrees with Lambinus that they are the work of Nepos, but that Probus probably abridged the biographies when he added the verse dedication. The Life of Atticus, however, is considered to be the exclusive composition of Nepos.