Lagarde had received numerous expressions of support from officials in Europe, the United States and Latin America, and as the sole candidate, the 60-year-old former French finance minister is virtually assured a second term.
At the same time Lagarde may hit a legal obstacle - she could face trial in France over her role in a banking scandal dating back to before she took the IMF job. Last December judges placed her under formal investigation over her alleged role in the long-running scandal over a large state payoff to former Adidas boss and politician Bernard Tapie.
Lagarde has said she will fight the trial order and the IMF board has declared its confidence in her.
The IMF executive board is expected to name the next managing director by 3 March.
Lagarde easily won the last contest in 2011, when several developing country candidates had vied to take over the IMF as Europe was sinking deep into economic crisis. But her victory came amid criticism that the IMF's top job should not be locked down by a European, as it has since the institution was created in 1944.