Net earnings in the second quarter totalled 20 million euros (USD 22 million), compared with 796 million in the same period of 2015.
Deutsche's performance fell well short of the average of 188 million euros expected by analysts surveyed by Factset.
"Our results show that we are undergoing a sustained restructuring," chief executive John Cryan said in a statement, adding that he was "satisfied with the progress we are making".
But the CEO warned that "if the current weak economic environment persists, we will need to be yet more ambitious in the timing and intensity of our restructuring".
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Pre-tax profits stood at 408 million euros -- a fall of 67 per cent compared with 2015's second quarter -- on revenue of 7.4 billion euros, down 20 per cent.
Revenues at Deutsche's brokerage division -- the bank's biggest source of income -- slumped by 28 per cent, or 924 million euros.
And the investment banking and wealth management units each saw drops, with revenues falling 12 percent and 11 percent.
Cryan is battling to convince markets and regulators that Deutsche is on course for recovery after it was described as a "major systemic risk" by the International Monetary Fund in June.
In early July the US Federal Reserve revealed that Deutsche's US arm had failed two sets of stress tests in a row.
Cryan is seeking to steady the ship, selling Deutsche's stake in the Chinese Hua Xia bank as part of efforts to boost its capital ratio.
"We've continued to de-risk our balance sheet, to invest in our processes and to modernise our infrastructure" over the second quarter, Cryan said.
European Banking Authority stress test results -- set for release on Friday -- will provide an initial indication of whether Deutsche's restructuring is convincing regulators.