Two men detonated explosives vests in Aviation Square, a commercial district and gathering point for day labourers seeking work, scores of whom were killed and injured, according to the official.
Iraq declared victory last month over Islamic State (IS) militants who seized control of nearly a third of the country in 2014. However, IS continues to carry out attacks and bombings in Baghdad and different parts of the country.
The attack in Aviation Square was one of the deadliest in Baghdad since a massive truck bomb killed at least 324 people in the nearby commercial district of Karrada in July 2016.
The Karrada bombing was the deadliest single attack in Iraq since the 2003 US-led invasion that ousted Saddam Hussein.