Gardai and emergency services attended the scene of an incident in Castlebar overnight.
The incident, involving a car and a cyclist, occurred at about 10 o'clock on the Springfield road outside Scoil Raifiteiri last night.
The cyclist was taken to Mayo university Hospital where his condition is described as serious but not life-threatening.
The street in front of Scoil Raifiteiri is currently cordoned off to allow for a technical examination and traffic is down to just one lane.
Gardaí are appealing for any witnesses to this incident to come forward.
Any road users who may have camera footage (including dash-cam) and were travelling along this route between 9:30 and 10:30 last night are asked to make this footage available to Gardaí.
Anyone with any information is asked to contact Castlebar Garda Station on 094 90 38200, the Garda Confidential Line on 1800 666 111 or any Garda Station.