Sales receipts in the 17-nation eurozone and the 27-member European Union dropped 1 percent and 1.1 percent, respectively, Eurostat said.
The declines follow a 0.3 percent rise in the eurozone in March and a 0.8 percent rise in March in the European Union.
Compared to April 2011, retail sales fell by 2.5 percent in the eurozone and 1.9 percent in the EU.
Sales of food, drinks and tobacco rose 0.63 percent in the eurozone and fell by 0.1 percent in the EU month to month. Sales of non-food items fell 1.4 percent in the eurozone and 1.2 percent in the EU month to month, the statistical office said.
Retail sales fell in 12 member states and rose in nine where data was available. The largest decreases were in Spain (off 9.6 percent), Portugal (off 9.3 percent) and Malta (off 4.6 percent). The largest increases were in Estonia (up 8.5 percent), Latvia (up 7.8 percent) and Romania (up 3.4 percent).