On 7 November 1975, during the 1975 coup, Chowdhury's wife, Nazia Osman was killed in his Gulshan residence. He retired from Bangladesh Army as a lieutenant colonel in 1976. In 2014 he was awarded the Independence Day Award for his contribution to the Bangladesh Liberation war. On 5 September 2020, he died at the Combined Military Hospital in Dhaka. Though he initially tested positive for COVID-19, a subsequent test did not detect the virus. Abu Osman Chowdhury was given a state funeral and buried at Banani Army Graveyard.