Police spokesman Stefan Sonntag has said that 150 people are injured in the crash, including 50 severely.
The two trains crashed head-on into each other shortly before 7am on the single line that runs next to the Mangfall river in Bad Aibling, Bavaria – 40 miles south-east of Munich.
German federal police told reporters that the crash took place “in an inaccessible region” and that rescue personnel are still working to free passengers trapped in the wreckage.
German police say the death toll in the Bavaria train crash has risen to eight.
Four people are reported to have been killed with another 150 injured in a head-on train crash in southern Germany.
The operator of the two trains, Bayerische Oberlandbahn, said on its website that the trains both partially derailed and are wedged into each other.
The operator and federal police in Bavaria have activated phone hotlines for families seeking information.
The statement did not address the cause of the crash, and officials declined to comment on it.
At least two people have been killed and about 100 more were injured - 10 seriously - in a train crash in southern Germany, police said.
Two regional trains were involved in the incident near Bad Aibling, in Bavaria, according to reports.
One train is reported to have derailed in the accident, with several carriages overturned.
Eight rescue helicopters were involved in rescue efforts near Bad Aibling, with further emergency staff making their way to the site.
Police spokesman Stefan Sonntag told reporters two regional trains crashed head-on on the single track between Rosenheim and Holzkirchen shortly before 7am local time.
Mr Sonntag said at least two people had died in the crash, but that the scene of the accident is so chaotic, there are no specific numbers over the amount of dead or injured.
"This is the biggest accident we have had in years in this region and we have many emergency doctors, ambulances and helicopters on the scene," Mr Sonntag said.
He added that some people are still trapped inside the wreckage, and rescue personnel are trying to free them.