A 67-year-old man was discovered in a property in East Church Close, just after 08:22 BST on Friday.
Police said they were satisfied the man's death was not suspicious.
A 41-year-old woman and a 43-year-old man arrested in connection with the man's death have been released without charge.
Police say they have not yet established a cause of death.
A man and woman arrested on suspicion of murder after a man was found in a Southampton house have been released without charge.