Ms Merkel is due to be sworn on Wednesday.
Parliament voted 364-315 in a secret list to re-elect Mrs Merkel, who ran unopposed.
Germany has been sealed in domestic doubt for almost 6 months after millions of electorate deserted the two categorical parties.
Ms Merkel’s Christian Democratic Union of Germany party (CDU) and the Social Democratic Party (SPD) were forsaken by the open in foster of parties on the left and right.
A bloc has been shaped between the CDU, the Christian Social Union (CSU) – which is the CDU’s Bavaria-only sister party – and the centre-left Social Democrats.
The organisation hold 399 of the 709 seats in parliament.
Germany is Europe’s biggest economy and has been led by Mrs Merkel given 2005.