Police were called by fire crews, who discovered the body after being called to a report of a minor blaze in Hyde Park Terrace.
It has not been confirmed whether the victim, who was found at about 19:00 GMT on Saturday close to Wrangthorn Church Hall, was male or female.
Two men, aged 37 and 50, are being held in custody, West Yorkshire Police said.
"Inquiries are obviously at a very early stage and we are yet to confirm the circumstances of this person's death," said Det Supt Simon Atkinson.
He appealed for witnesses to contact police or Crimestoppers on 0800 555111.
Two men have been arrested on suspicion of murder after a body was found in Leeds.