The Online Catalogue for the Barcelona Municipal Archives has more than 500,000 document descriptions on the municipal government and city authority. It also offers information on other sources and private collections. Some of its descriptions contain images.

The catalogue's current information represents but a small fraction of documents kept at the city's archives centres, as those centres in fact house 40 km of text documents, over three million photographs and thousands of cartographic, graphics and sound documents.

Where requests for copies are for commercial, publication or distribution purposes, these must be sent directly to the archives centre the original material is kept at, to ensure intellectual property rights and use of the images.