A call came into police from the local ambulance service at 3:23 p.m. GMT (11:23 a.m. EDT) Saturday saying a man had been found dead, Thames Valley Police said in a statement on Sunday.
The police said an employee of Berezovsky told how he had called an ambulance after becoming concerned for Berezovsky's welfare and forced open a bathroom door locked from the inside to find the tycoon's body on the floor.
The employee was the only person in the house when Berezovsky's body was discovered, police said. Members of the ex-oligarch's family arrived at the home while the paramedic was on scene.
Thames Valley Police said there was no evidence to suggest "third party involvement" and are now asking his friends and family about his "state of mind" in the weeks before his death.
Boris Berezovsky was found dead at his Berkshire home on March 23.