Japanese automakers sold 132,838 cars in Germany last year, amounting to a 11.6 market share.
Non-German brands sold 1,145,158 units for a 35.1 percent market share, down slightly from 35.4 percent in 2003.
The Japanese brands are back on top for the first time since 2001.
They overtook French manufacturers Renault and PSA/Peugeot-Citroen, whose market share dropped to 10.6 percent from 12.1 percent.
Sales of models imported to Germany from the Czech Republic grew to 3 percent from 2.7 percent last year.
South Korean automakers' market share grew to 3 percent from 2.3 percent.
Sales of new-cars imported from Italy dropped to 2.5 percent from 2.7 percent.
In 2004, 3,266,826 units were sold in Germany, according to ACEA, the European car manufacturers association.
Volker Lange, president the German Association of Motor Vehicle Importers (VDIK), thinks that in a few years the importers' market share could rise to 50 percent.