Fuel sales rose 3.5% on the month in May in data adjusted for the number of working days and seasonal factors, INS said.
On the other hand, sales of food, drinks and tobacco declined 1.9% in May from the previous month, while sales of non-food items were down 1.6%.
In annual terms, adjusted retail sales fell 6.4% in May, due to declines in all sectors.
Sales of food, drinks and tobacco were down 10.3% in May from the same month a year earlier, while Sales of non-food items decreased by 3.9%. Fuel sales slid 3.8% on the year in May.
In the January to May period, Romanian adjusted retail sales declined 5.9% on the year, again due to falling consumption in all sectors, the data showed.