I am looking for information on Austro-Hungarian soldiers who died in the First World War

There is no comprehensive list or index of all war casualties of the Habsburg Monarchy.

During the war lists of casualties sustained by the Austro-Hungarian armed forces were published in print (OÖLB). These include the wounded and prisoners of war. There are also special lists of the sick and wounded (Nachrichten über Verwundete und Kranke).

These published lists provide surname, first name, rank, year of birth, “Heimatzuständigkeit”, military unit and, for prisoners of war, the prisoner camp (if known).

For the Hungarian war dead there is a special database.

The original casualty reports which were sent to the central authorities in Vienna and on which the published lists are based very rarely contain significant supplementary information. For conservation reasons they are no longer made available for consultation in the reading room.

There is a Totenkartei des Ersten Weltkriegs.Theindex cards provide the following details: surname, first name, rank, military unit, year of birth, “Heimatzuständigkeit”, place and date of death, burial place.

The “Totenkartei” is far from including cover all Austro-Hungarian war dead.

The “Totenkartei” is available online.

The wartime military registers of deaths (“Kriegsmatriken”) have been digitised for those who died in military hospitals in Vienna and Lower Austria and for conscripts of regiments which had their recruiting districts in Vienna, Lower Austria or the Pressburg/Bratislava/Pozsony area (including what is now the Austrian province of Burgenland).

You can find a list of the digitised “Kriegsmatriken” here.

As there is no general index of the deceased, the hospital in which the person concerned died has to be identified first.

The Kriegsarchiv holds ten volumes of post-war “Ehrenbücher“ in which the war dead from Vienna, Lower Austria, Burgenland, Styria, Carinthia, Tyrol, Vorarlberg, Salzburg and Upper Austria were registered. These lists, often incomplete, are organized by province, district and municipality and may provide surname, first name, rank, military unit, year of birth, date and place of death.

For the Tyrolese war dead there is the Tiroler Ehrenbuch (online).