What year does Dragon Ball Z take place?

Goku meets Bulma around 749 AD (keep in mind that while it is Earth, it's all one writer's imagination and so it can be considered an alternate universe). Goku was about 11 at the start of Dragon Ball, and Bulma was 16. They are around 23 and 28, respectively, when Dragon Ball Z starts, so that would mean that DBZ takes place in the year 761 AD -- or some time around that.