The leu opened at 4.30/4.303 against the euro, compared to 4.3025/4.3050 at closing Friday.
Within the first hour of trading, the leu weakened slightly and, at around 10:00 local time, it was trading at 4.3015/4.3035 against the euro.
The central bank published Friday a leu-to-euro reference rate of 4.3072 units.
On the money market Monday morning, overnight rates jumped to 5.8%-6.3% a year, from 3.8%-4.3% a year in the previous session.