Codex Basilensis is a Greek uncial manuscript of the four Gospels written on parchment.

The manuscript is a codex (precursor to the modern book) containing an almost complete text of the four Gospels on 318 parchment leaves (sized 23 × 16.5 centimetres (9.1 × 6.5 in)).

[3] The letters Θ (theta) Ε (epsilon) Ο (omicron) and Σ (sigma) are round, the strokes of Χ (chi) Ζ (zeta) Ξ (xi) are not prolonged below the line.

[3] The initial letters at the beginning sections stand out on the margin as in codices Alexandrinus and Ephraemi Rescriptus.

[5]: 132  The page margins also contain the names of Feast days and their lecton references, together with other liturgical notes.

[7] The Greek text of this codex is considered a representative of the Byzantine textual tradition, but with a small number of non-Byzantine readings.

These are then used to determine the original text as published; there are three main groups with names: Alexandrian, Western, and Byzantine.

[8]: 205-230  The text of the manuscript has been cited in all critical editions of the Greek New Testament, but it is not highly esteemed by scholars.

Dean Burgon proposed the 7th century due to the shape of the letters, but the names of Feasts days with their proper lessons and other liturgical markings have been inserted by a later hand.

[7] It was probably brought to Basel by Cardinal Ragusio (1380–1443),[3] who may have acquired it in Constantinople[5] when he attended the Council of Florence in 1431.