The US bank reported a profit of $3.5bn (£2.5bn), down from $4.8bn in the first quarter of 2015.
The company's revenue during the period was $17.56bn, down 11 per cent from $19.7bn. Its investment banking revenues for the quarter were $875m, down 27 per cent.
Earnings per share (EPS) for the period was $1.10, down from $1.51 in the first quarter of 2015.
The figures are slightly ahead of expectations. Consensus estimates from Thomson Reuters had called for $1.03 EPS and $17.46bn in revenue.
Citigroup cut costs by three per cent to $10.5bn during the period.
Why it's interesting
Citigroup posted its first-quarter earnings today, following the likes of Bank of America, Wells Fargo and JP Morgan Chase.
Wells Fargo reported its profits were down seven per cent over the last three months compared with last year. This was not as bad as expected, and EPS was $0.99, ahead of a $0.97 forecast.
On Wednesday, JP Morgan's profits came in at $1.35 a per share, on revenue of $24.1bn. Analysts were expecting an EPS of $1.24 on revenue of $23.80bn, according to a Bloomberg poll.
Bank of America's first-quarter results were less clear cut. Profits slumped by 13 per cent to $2.68bn from $3.1bn last year. Revenue came in under expectations, but an EPS of $0.21 matched analysts' expectations.
Morgan Stanley and Goldman Sachs report on Monday and Tuesday next week respectively.
What the company said
Chief executive Michael Corbat:
While our market-sensitive products clearly suffered from weak investor sentiment during the quarter, we continued to make progress in several key areas. We grew loans and deposits in our core businesses, reduced our expenses while absorbing a significant repositioning charge, utilized additional Deferred Tax Assets, and generated capital in excess of what we returned to our shareholders. Our Common Equity Tier 1 Capital ratio now stands at 12.3% and our Tangible Book Value per share increased to $62.58.