PART of the TT course was closed for four hours last night following a collision at Handley's Corner on the Ballacraine to Kirk Michael road.
It involved a white VW van driven by a 52 year old Ballaugh man and a silver Volvo driven by a 72 year old Andreas man.
Both men were taken by ambulance to Noble's Hospital. The 52 year old was detained with serious injuries believed to be non life threatening.
It happened at 5pm and the road was closed for just over four hours while police carried out investigations.
Head of the roads policing unit Inspector Mark Britton said: "I apologise for any inconvenience caused to road users last night during the road closure.
"Essential investigations needed to take place. It was unclear as to the exact condition of either of the drivers at the time of the attendance of the emergency services and our priority was ensuring that the scene was managed in a safe way."
Anyone who witnessed either of the vehicles either at the time or just prior to the collison should contact the roads policing unit on 631212.