The tasks of the Wiesbaden City Archive are regulated in the Hessian Archive Act (HArchivG) and in the Statutes on the Archiving of Documents of the State Capital of Wiesbaden (Archive Statutes), which were last amended in 2021.
As the public archive of the state capital of Wiesbaden, the city archive evaluates the documents created by the Wiesbaden city administration and by the associations and legal entities under public law subject to the supervision of the state capital of Wiesbaden with regard to their political, legal, economic, social or cultural significance for researching and understanding the history and present of Wiesbaden.

Once the archivists have made this decision about the value of the documents, the city archive takes over the documents worthy of archiving for permanent storage in the city archive. Documents are not only documents, official records, files, other documents, official publications or paper files. The Wiesbaden City Archive is also responsible for plans, posters, seals, stamps, image, film and sound recordings as well as all digital recordings, regardless of their storage form, which are created by the offices of the state capital. In addition, the City Archive also accepts archive material from private bodies such as the estates of important personalities, club, association or company documents to complete its holdings. The aim is always to document and preserve the history of Wiesbaden in as many facets as possible and thus the work of people in the city.

The documents and files are stored safely and securely in the city archive, restored if necessary and made accessible for use through the so-called indexing process. To this end, the archivists at the city archive record the documents they have received in a database, which enables them to be retrieved quickly from the repository and presented to users at a later date.

The approximately five and a half kilometers of files and other archive material currently stored in the Wiesbaden City Archive are used by the archivists to answer around 3,000 verbal and written inquiries per year and for presentation to around 350 users in the reading room each year. In addition to the archival records, the city archive provides information on the history and present of the city of Wiesbaden via a scientific reference library.

The statutory tasks of the Wiesbaden City Archive also include advising the departments, offices and municipal enterprises of the state capital of Wiesbaden on the management, storage and safeguarding of their documents. The City Archive is to be involved in all measures relating to the management of the city's records. It is also involved in the planning, introduction and significant changes to IT systems and software in this area.

In addition, the archivists are dedicated to scientific research into the history of the city of Wiesbaden. They support civic, educational and scientific actors in researching the city's history and thus contribute to the cultural life of the state capital. In addition, the city archive manages the historical memorials of the state capital of Wiesbaden as places of collective remembrance, scientific research and historical-political education, especially on the history of Nazi rule.

As a training center, the City Archive is also involved in the training and further education of archival specialists and presents the professional field of archives to interested students in internships accompanying their studies.