Patrolling police officers saw a house on fire in Bishopric, Horsham, at 7.30pm
Police confirmed an elderly man, who was living there, was sadly confirmed deceased at the scene.
Another elderly man found at the address is being treated at hospital for some burn injuries to his hands and smoke inhalation but his condition is not assessed as life threatening.
A spokesperson said the incident is being treated as unexplained but not suspicious at this stage.
West Sussex Fire and Rescue Service posted on Twitter just after 8.15pm, asking residents to avoid Bishopric in Horsham 'while the fire is brought under control'.
Crews from Billingshurst, Crawley and Horsham were at the scene of the incident, which was described as 'serious' by eye-witnesses on social media. A police car was also pictured outside the property, where cordons had been set up.