|Full name||Mark Downey|
|Born||3 July 1996|
Dromore, County Down, Northern Ireland
|Height||1.83 m (6 ft 0 in)|
|Weight||74 kg (163 lb)|
|Current team||Côtes d'Armor–Marie Morin–Véranda Rideau|
|2020–||Côtes d'Armor–Marie Morin–Véranda Rideau|
On the track he competed at the 2015 UEC European Track Championships in the points race and team pursuit. He won the gold medal at the 2016–17 UCI Track Cycling World Cup, Round 2 in Apeldoorn in the points race. He also won the third round of the World Cup points race held in Cali, Colombia following that event he picked up a silver in the madison with his teammate Felix English. Concluding his 2017 World Cup campaign Downey won the madison in LA round 4 and was overall series winner in the points race.
- 5th Time trial, National Road Championships
- 1st Points race – Apeldoorn, 2016–17 UCI Track Cycling World Cup
- 1st Stage 6 Tour Nivernais Morvan
- 2nd Points race, UEC European Under-23 Track Championships
- 2016–17 UCI Track Cycling World Cup
- 3rd Points race, UEC European Under-23 Track Championships
- 9th Road race, UCI Under-23 Road World Championships
- 3rd Road race, National Road Championships
- 3rd Overall Volta ao Alentejo
- 4th Road race, Commonwealth Games
- 4th Clássica da Arrábida
- 3rd Points race, UCI Track World Championships
- Gachet, Nicolas (31 October 2019). "Trois derniers renforts pour Côtes d'Armor-Marie Morin-Véranda Rideau" [Last three reinforcements for Côtes d'Armor-Marie Morin-Véranda Rideau]. Directvelo (in French). Association Le Peloton. Retrieved 26 March 2020.
- "Results 2016–17 UCI Track Cycling World Cup". Tissot Timing. November 2016. Retrieved 19 November 2016.
- "2016–17 UCI Track Cycling World Cup Entry List Men". Tissot Timing. November 2016. Retrieved 19 November 2016.