For All the Saints: Peter Damian
- Overview of the saint's life and character.
- http://www.saintpatrickdc.org/ss/0221.htm#pete

Catholic Encyclopedia: St. Peter Damian
- Cardinal, Doctor of the Church. Died in 1072. Biographical article.
- http://www.newadvent.org/cathen/11764a.htm

Sacred Heart Parish: St. Peter Damian
- Brief, entertaining, biographical sketch.
- http://www.hullp.demon.co.uk/SacredHeart/saint/StPeterDamian.htm

Saint Peter Damian, or of Damian, Cardinal, Bishop of Ostia
- From Alban Butler's Lives of the Saints.
- http://www.cin.org/saints/petedami.html

Peter Damian, Saint
- Short biographical entry in the Columbia Encyclopedia.
- http://www.bartleby.com/65/pe/PeterDam.html

Vietnamese Eucharistic Youth Society: St. Peter Damian
- The story of his life, suited to children. Formatting can make this hard to read.
- http://www.tntt.org/vni/tlieu/saints/St0221.htm

Patron Saints Index: Peter Damian
- Profile. Never formally canonized, although he is a Doctor of the Church. With links.
- http://www.catholic-forum.com/saints/saintp25.htm