The 1st constituency of the Côtes-d'Armor is a French legislative constituency in the Côtes-d'Armor département in Brittany.

Like the other 576 French constituencies, it elects one MP using the two-round system, with a run-off if no candidate receives over 50% of the vote in the first round.

The constituency is anchored by the town of Saint-Brieuc.

* PS dissident** Horizons dissident