The coroner's office says Ronald Bertram Greaves died of prostate cancer on Sept. 27 at his home.
"Take a Letter, Maria," about a man's final letter to his cheating wife, hit No. 2 on the Billboard chart and went gold. The song, with its soul style and brassy horn edge, went on to sell more than 2.5 million copies and remains a popular oldie.
Greaves also broke into the Top 40 in 1970 with his version of "(There's) Always Something There to Remind Me."
His career flagged in the 1970s, however.
Greaves was a nephew of the legendary R&B singer Sam Cook.