Soldado has become Tottenham's most expensive player, arriving from Spain for around £26m.
The Spain international is expected to make his debut against familiar opposition, when Spurs host Espanyol on 10 August.
A statement from Tottenham read: "We're delighted to confirm the signing of Roberto Soldado from Valencia after successfully completing his medical."
Soldado began his career at Real Madrid, but three years ago he moved back to his hometown club, where he scored 30 goals in 46 games last season.
The capture of Soldado means Spurs have broken their transfer record twice in four weeks, with Paulinho's £17m arrival in July eclipsing the £16m fee the club paid for Luka Modric in 2008.