Consumer prices in the 16-country currency area rose 1.5 percent year-on-year, up from 1.4 percent in March, European Union statistics office Eurostat estimated.
No monthly data or detailed breakdown was available. The details will be released on May 18.
In March, price rises were driven mainly by higher energy costs.
The ECB wants to keep inflation just below 2 percent over the medium term. Economists expect the bank to hold interest rates at a record low of 1 percent until next year.