A deal could see Karstadt combined with Metro's stores
Metro, Germany's biggest retail group, wants to buy the assets of collapsed retailer Arcandor.
Arcandor, which owns 53% of travel firm Thomas Cook, filed for bankruptcy on Tuesday after the German government declined to bail it out.
"We have a short and medium-term objective to create a large new ensemble," Metro boss Eckhard Cordes told the ZDF television channel.
Mr Cordes suggested the combination could be listed as a new company.
Arcandor's bankruptcy filing covers German retailer Karstadt and its mail-order businesses, but Thomas Cook is a separate operation and Arcandor said the travel company would "remain unaffected".
Metro would merge its Kaufhof chain of stores with Karstadt and retain about 160 of the combined 200 department stores, Mr Cordes said.
The combined company could be sold after two years of restructuring via a stock market listing, a spokesperson told the Handelsblatt newspaper.
Metro had been in talks with Arcandor on a merger of their department stores before the bankruptcy.
Arcandor, which employs about 70,000 people, had sought 650m euros ($930m; £561m) of loan guarantees from the German government because about 600m euros of its loans needed refinancing.
The German government was reluctant to help Arcandor, because the company was in trouble before the economic crisis. Shares in the company have dropped more than 70% this year, and they fell 81% last year.