Ann Mercken (born 6 May 1974 in Hasselt^[1]) is a retired Belgian athlete who specialised in the 400 metres hurdles.^[2] She represented her country at the 1996 Summer Olympics reaching the semifinals. She also competed at the 1999 World Championships.

Her personal best in the event is 54.95, set in 1996. This was the national record until Paulien Couckuyt improved it to 54.90 at the 2020 Summer Olympics.

Competition record

Year	Competition	Venue	Position	Event	Notes
Representing  Belgium
1995	Universiade	Fukuoka, Japan	6th	400 m hurdles	56.65
1996	Olympic Games	Atlanta, United States	12th (sf)	400 m hurdles	54.95
1998	European Championships	Budapest, Hungary	18th (h)	400 m hurdles	57.39
1999	Universiade	Palma de Mallorca, Spain	8th	400 m hurdles	56.05
	World Championships	Seville, Spain	21st (h)	400 m hurdles	55.84
2001	Universiade	Beijing, China	5th	400 m hurdles	56.42
2002	European Championships	Munich, Germany	11th (h)	400 m hurdles	57.02