A collision closed a portion of Highway 7 near Breslau on Tuesday morning.
Police were called to Victoria Street North and Spitzig Road around 7:30 a.m. for the crash.
Sgt. Kerry Schmidt with the OPP tweeted that a 40-year-old male cyclist had died in the crash.
He was from the Kitchener area but of no-fixed address, police said.
Waterloo Regional Police were on scene to direct traffic and could only say the collision was serious.
Ontario Provincial Police are in charge of the investigation.
Highway 7 was closed between Shantz Station Road and Fountain Street and caused heavy delays for drivers during the morning commute.
The scene was cleared and the road reopened before noon.
A 40 year old male cyclist from the Kitchener area is dead after being struck by a vehicle on #Hwy7 at Spitzig Rd #Kitchener
— Sgt Kerry Schmidt (@OPP_HSD) September 4, 2018
Be Alert #DriveSafe#BackToSchool pic.twitter.com/6R4kJJNSIG