"There is no longer you and us. Now there is only one Europe shared," Buzek, who is from the conservative European People's Party, said.
Jose Manuel Barroso, president of European Commission - the EU's executive arm - said Buzek's election was a sign that European integration had been a success.
"Twenty years after the Berlin Wall came down, five years after enlargement, your election today is, I think, a resounding victory for a united Europe"
Jose Manuel Barroso,
European Commission president
"Twenty years after the Berlin Wall came down, five years after enlargement, your election today is, I think, a resounding victory for a united Europe," he told the parliament.
Buzek replaces Hans-Gert Poettering, from Germany, for two-and-a-half years, before handing over to Martin Schulz, the socialist bloc leader, under an arrangement between the left and right-wing factions, the biggest in the assembly.
The former Polish prime minister headed a coalition government from 1997-2001, and has been a member of the European Parliament since 2004.
He was also a member of the pro-democracy Solidarity trade union which ended Communist rule in Poland in 1989.
His post, while symbolic for eastern European states, is largely ceremonial, and holds little influence over the assembly.
The European parliament examines, amends and endorses thousands of European rules which effect the lives of around 500 million people.