Eighty-six days after Merkel, 59, swept to victory in elections but failed to grab an outright majority, the Bundestag lower house of parliament will vote on handing her another four-year term.
The ballot is secret but the outcome likely holds little surprise.
With a whopping 504 of the 631 seats, Merkel's conservatives and their new centre-left partners, the Social Democrats (SPD), hold a comfortable majority under their hard-fought 'grand coalition' deal.
The ceremony and later swearing-in of ministers followed by the first cabinet meeting will enable Merkel to finally get back down to business in earnest after the longest government-building period since World War II.
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Merkel is then due to address parliament tomorrow and travel to Paris for talks with President Francois Hollande the same day, ahead of an EU summit at the end of the week.
A parliament debate after tomorrow's address will be the first opportunity for a face-off across the floor since the SPD moved off the opposition benches.
Few observers doubt though that the road ahead will be bumpy.
Having wrested concessions from the conservatives in negotiations to pave the way for the new coalition, SPD chief Sigmar Gabriel, the new vice chancellor and economy and energy minister, will need to impose his party's imprint on the new government to avoid the costly mistakes of its first tie-up with popular Merkel.