Carmarthen West and South Pembrokeshire (Welsh: Gorllewin Caerfyrddin a De Sir Benfro) is a constituency of the House of Commons of the Parliament of the United Kingdom. It elects one Member of Parliament (MP) by the first past the post system of election. The Carmarthen West and South Pembrokeshire Senedd constituency was created with the same boundaries in 1999 (as an Assembly constituency).