The Codex Ephraemi Rescriptus designated by the siglum C or 04, δ 3, is a manuscript of the Greek Bible, written on parchment. It contains most of the New Testament and some Old Testament books, with sizeable portions missing. It is one of the four great uncials. The manuscript is not intact: its current condition contains material from every New Testament book except 2 Thessalonians and 2 John; however, only six books of the Greek Old Testament are represented. It is not known whether 2 Thessalonians and 2 John were excluded on purpose, or whether no fragment of either epistle happened to survive.

A biblical manuscript is any handwritten copy of a portion of the text of the Bible. Biblical manuscripts vary in size from tiny scrolls containing individual verses of the Jewish scriptures to huge polyglot codices containing both the Hebrew Bible (Tanakh) and the New Testament, as well as extracanonical works.