Only last month it was revealed that the singer, whose many hits include "You'll Never Find Another Love Like Mine," was battling cancer of the lung and brain.
At the time, Rawls told the Arizona Republic, "Don't count me out, brother."
The lung cancer was diagnosed in 2004 and the brain cancer the following May, Rawls's estranged wife, Nina, said during a marriage annulment hearing in December in Arizona. The singer lived in Scottsdale.
The divorce was acrimonious, with Rawls's stating in court papers that he was trying to annul his 2-year marriage and protect hundreds of thousands of dollars of assets that he contended his wife "absconded with," reported the Associated Press.
Nina Rawls, 35, a former flight attendant who has worked as her estranged husband's manager since 2003, said she transferred nearly $350,000 into an account that she solely controls to prevent one of Rawls's adult daughters from seizing the funds.
Rawls's previous marriage, to Lana Rawls with whom he had three children, ended in divorce. He also had a child with Nina.
Jason Moore / ZUMA
The singer was playing small blues and R&B clubs in Los Angeles when he caught the ear of a Capitol Records producer, who signed him to the label in 1962. His 1966 hit, "Love Is a Hurtin' Thing," topped the charts and earned Rawls two Grammy nominations. He received 13 during his career.
Besides the recordings that highlighted his four-octave range – and drew admiration from fellow crooner Frank Sinatra – Rawls also lent his voice to the 1998 Rugrats movie and appeared the same year in the movie Blues Brothers 2000.
Rawls released his most recent album, Seasons 4 U, in 1998 on his own label, Rawls & Brokaw Records.
He is survived by his four children, Louanna Rawls, Lou Rawls Jr., Kendra Smith and Aiden Rawls.