At least one woman was killed in the crash, Austrian police said. Another 22 people were injured, including three children.
Austrian Federal Railways (ÖBB) said that several of the passengers were seriously injured. Dozens of others were also being treated for shock.
Following news of the crash, Austrian Chancellor Sebastian Kurz tweeted that his thoughts were with the family and friends of the victim.
"I wish all the injured a quick recovery. Thank you to all emergency personnel who are helping on site!"
Windows ripped off EuroCity trainThe EuroCity216 train, which is run by German rail operator Deutsche Bahn, was traveling from the Austrian city of Graz to the German city of Saarbrücken when it struck a local Austrian passenger train.
The so-called "flank-collision," where the trains crashed into each other's sides, occurred shortly before 1:00 p.m. local time (1200 UTC) at a train station in the Austrian town of Niklasdorf.
The force of the crash ripped off a row of windows on the EuroCity train.
Although the cause of the crash remains unclear, the trains appeared to hit each other at a switch point where the trains are closer together.
rs/kms (AFP, dpa)