Draghi stressed that overall growth is expected to remain solid and broad based, and ample liquidity is necessary to bring the inflation back to 2 percent target.
With eurozone growth still strong by historical standards, most economists expect the European Central Bank to phase out its bond purchases by December - four years after the Federal Reserve halted its own QE program - and to start raising interest rates late next year.
The ECB's decision to stand pat had been expected, but Mr. Draghi's caution suggests the ECB could yet delay a decision to phase out its EUR30 billion ($36.6 billion)-a-month bond-buying program, known as quantitative easing or QE, which is now due to run at least through September.
The rates on the main refinancing operations and the interest rates on the marginal lending facility and the deposit facility will remain at 0.00%, 0.25% and minus 0.40%, respectively.
Economists polled by Reuters still expect bond purchases to end this year after a short taper and see the first rate hike in the second quarter of 2019, but some have started to flag risks of a delay.
"Euro/dollar continues to fall as long positioning gets pared back against a backdrop of negative realised returns and we remain tactically bearish on the pair", the analysts said.
Robert Sierra, of Fitch Ratings said: "Along with the recent flat core inflation numbers and Draghi's emphasis in the press conference on the impact of the stronger euro on inflation, the ECB's tone has become slightly more dovish".
With the bond-buying scheme due to expire in September, the European Central Bank will have to decide in June or July whether to extend purchases or wind them down.
Business confidence in the 19-country bloc has already taken a knock, most notably in export-focused Germany.
A key worry is that protectionist rhetoric from the United States could push down the value of the dollar even as the Federal Reserve is likely to raise interest rates several times this year, to support the USA currency.
This suggests that the euro zone's economic downturn was more severe than earlier thought and makes the recovery even more protracted.
World markets remained edgy on Thursday, with shares eking out gains amid concern over the global economic outlook and with USA bond yields at four-year highs after breaking above the psychologically significant 3 percent line this week.