The incident happened on Huddersfield Road in Lees just after 5pm.
After an air ambulance was mobilised, the cyclist was taken to hospital with serious injuries following the smash.
This morning (Friday), police have confirmed that the cyclist had died.
Details of the cyclist's age or gender haven't been revealed.
A man was arrested at the scene on suspicion of driving whilst unfit through drink or drugs.
A Greater Manchester Police spokesperson said: "At around 5.15pm on Thursday 6 August 2020, police were called to reports of a collision between a cyclist and a van on Huddersfield Road in Lees.
"Emergency services attended and the cyclist was taken to hospital with serious injuries.
"A 35-year-old man was arrested at the scene on suspicion of driving whilst unfit through drink or drugs.
"He remains in custody for questioning and enquiries are ongoing."
Anyone with any information is asked to contact GMP’s Serious Collision Investigation Unit on 0161 856 4741 quoting incident number 2342 of 06/08/2020, or the independent charity Crimestoppers, anonymously, on 0800 555 111.
