Saint Ildefonsus is a 1609 painting by El Greco.

It and his Saint Peter were both painted for the Church of San Vicente, Toledo.

It has also previously been misidentified as Pope Eugene I or saint Blaise.

Ildefonsus is shown in a chasuble, pallium and mitre, holding a bishop's staff and an open book.

The full robes emphasise the model's anatomy, showing Michelangelo's influence on El Greco.