Cogitosus (fl. c. 650) was an Irish monk and writer. Cogitosus was a monk of Kildare who wrote the oldest extant vita of Saint Brigit, Vita Sanctae Brigidae, around 650. There is a controversy as to whether he was related to Saint Brigit.
- Bitel, Lisa M (2002). Textual Practice Summer 2002, Vol. 16 Issue 2. Academic Search Premier (EBSCOhost). P. 211.
- Herbermann, Charles, ed. (1913). "Cogitosus". Catholic Encyclopedia. New York: Robert Appleton Company.
- The Journal of the Royal Society of Antiquaries of Ireland, 1987, Vol. 117, p. 5 ff., Cogitosus's Life of St Brigit: Content and Value (commentary by Sean Connolly) followed on page 11 ff. by 'Cogitosus's Life of St Brigit' translated by S. Connolly and J.-M. Picard, accessed 13 February 2012
- St Patrick's World, Liam de Paor, Four Courts Press, Dublin, 1993 - chapter 33, Cogitosus's Life of St Brigid the Virgin, accessed 13 February 2012