The tanks were sold to industry as part of defence cuts after the Cold War. The German defence ministry said it would spend €22m (£16m;$24m) on bringing its total of tanks to 328.
Nato officials agreed in February to create a quick-reaction force to meet the challenges posed by the Ukraine crisis and by Islamic extremists. Nato defence ministers have also agreed to more than double the size of the alliance's Response Force.
The moves were seen as a signal that Nato regards Russia's seizure of Crimea and its military forays into eastern Ukraine as much more than a temporary crisis.
German defence ministry spokesman Jens Flosdorff confirmed a report by Der Spiegel (in German), saying 100 Leopard 2 battle tanks will be bought back from the defence industry, which has kept them in storage.