The Frankfurt institution left the rate on its main refinancing operations at zero, on its marginal lending facility at 0.25 percent and on its deposit facility at -0.4 percent.
Monetary policymakers gathered in Frankfurt ahead of an evening meeting of EU leaders in Brussels, set to decide whether to grant the UK a second delay to avoid Friday's no-deal deadline.
Prime Minister Theresa May must present a credible plan for passing a deal through London's fractious parliament to secure an extension from the EU, Brussels' chief negotiator Michel Barnier said Tuesday.
In Frankfurt, the central bank fears a no-deal Brexit could spark tumult on financial markets and further undermine anaemic growth in the 19-nation eurozone.
A familiar string of other threats are also weighing on confidence and activity in the bloc, including US-China trade talks and Washington's threat of harsh tariffs on European goods.
In his 2:30pm (1230 GMT) appearance before journalists, ECB chief Draghi "will have no choice but to give a downbeat assessment of the economic outlook," Capital Economics analyst Jack Allen predicted.
And given the clouds ahead, the top central banker is likely to underscore that the ECB has tools at its disposal to fight any additional fires, analysts said.