The Italy forward, who was top scorer in Serie A last season with 22 league goals, has joined the German giants on a five-year deal from Torino
The 24-year-old, who was top scorer in Serie A last season for Torino, scoring 22 goals in 33 league games, will replace Robert Lewandowski, who is moving to Bayern Munich.
The Bundesliga giants' sporting director Michael Zorc believes the Italy international is a great signing for the club and believes he will fit into Jurgen Klopp's team perfectly.
"In Ciro Immobile we have got a flexible and dynamic attacker who has succeeded in an impressive way in a top European league," he told the club's official website.
"He will fit in perfectly with the outstanding qualities required by Borussia Dortmund."
Immobile's 22 league goals helped fire his club to seventh in Serie A and a place in next season's Europa League, after Parma, who finished sixth, were excluded from the competition for failing to pay a tax bill.
The forward has since been rewarded for his form by being included in Italy's final 23-man squad for the World Cup in Brazil, this summer.
He also started their last warm-up game, a 0-0 draw at Craven Cottage on Saturday, which was marred by Riccardo Montolivo's broken leg - which ruled him out of this summer's tournament.