A motorcyclist was killed instantly when he lost control of his machine, which crashed head-on with a car.
The 38-year-old rider, from Bognor, was riding north on the A285, near Droke Lane at Upwaltham, near Petworth, when the crash happened at 8.25am on Friday.
A police spokesman said: "He appears to have lost control for reasons unknown and became involved in a head-on collision with a red Rover Maestro."
The 38-year-old Maestro driver, from Horsham, was seriously injured and taken to St Richard's Hospital, Chichester.
The dead man, who was riding a green Honda motorcycle, has not yet been named.
Anyone with information should call Chichester traffic police on 01243 520239.
A cyclist has died after she was involved in a crash with a car.
Rosemary Muller, 77, from Haresfoot Close in Funtington, near Chichester, died on April 4 at Worthing Hospital.
The collision happened at 7.53am on March 24 in Church Lane, Funtington.
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