Large numbers of people laid flowers in the shadow of the enormous Soviet Victory Memorial to a soundtrack of wartime songs.
The event is not celebrated by Latvia's Latvian majority which generally views Soviet "liberation" as the start of a second, 45-year occupation by Moscow.
It is not a public holiday.
A heavy police presence attempted to keep traffic moving as much as possible while patrols stalked the park nearby to discourage people drinking in public.
Several lower-key official events on the other side of the River Daugava ware being held to mark Europe Day instead.
May 8 saw Prime Minister and other dignitaries paying tribute to the victims of World War II.
