Sidecar crew Nicky Crowe and Mark Cox both suffered 'significant injuries' in a crash on the approach to Ballaugh, on the first lap of this evening's Sidecar 2 race.
The Manx driver, and his passenger from Rochester in Kent, were airlifted to Noble's Hospital.
Following the accident, at Ballacob, TT organisers took the decision to abandon the race, which means it won't be re-run.
In a media release this evening, TT organisers said Crowe, who is 38 and from Jurby, and Cox, 39, were being 'evaluated' in hospital.
As well as the sidecar race, a Senior practice session was cancelled, which won't be rescheduled either.
The racing calendar for Friday remains as advertised in the race programme.