In the 27-nation EU, sales slid 1.1 percent. In the eurozone, comprised of 17 nations that share the euro as currency -- sales dropped 1.2 percent month to month, Eurostat said.
Eurostat also announce downwardly revised figures for September with sales down 0.2 percent in the EU and 0.6 percent in the eurozone.
Previously, Eurostat reported a 0.1 percent gain in the EU and a 0.2 percent drop in the eurozone.
October's drops in both the EU and the eurozone were pushed by a 0.8 percent drop in both regions in food, drinks and tobacco sales.
With data unavailable or withheld by six countries, Eurostat said Ireland posted the largest gain for October with sales up 1.9 percent, followed by Lithuania (up 0.8 percent) and Belgium, (up 0.7 percent).
Sales declined fastest in Portugal (down 4.5 percent), Finland (down 3 percent) and Germany (down 2.8 percent).