Improved tax collection, spending cuts and delayed payments lifted the surplus to 2.6 percent of GDP in the first four months of the year.
Finance Minister Vladislav Goranov told deputies last week he expected the country to outperform on its annual budget target for a 2 percent fiscal shortfall, but warned that most investment spending is planned for the second half of the year.
The European Union's poorest member state ended 2015 with a fiscal shortfall worth 2.9 percent of GDP.
Better tax collection and tightened controls over excise duties helped the ruling centre-right coalition to trim the budget shortfall this year.
Government revenue at the end of April rose 7.4 percent from a year before to 12.2 billion levs ($6.95 billion).
Spending dropped to 4.3 percent to 9.8 billion levs a year ago, finance ministry data showed.
Fiscal reserves held under a currency regime pegging the lev to the euro stood at 12.3 billion levs at the end of April.
Goranov has said he hopes economic growth in 2016 will mirror last year's 3 percent expansion.
The official government forecast for growth, however, is set at 2.1 percent.
The economy grew by 2.9 percent in the first quarter on an annual basis.