The purpose of an ERCIM working group is to build and maintain a network of ERCIM researchers in a particular scientific field. A working group is open to anybody affiliated with an ERCIM institute that has decided to participate in the working group. An ERCIM institute participates in the working group, as soon as the ERCIM Board of Directors approves of its creation, after a recommendation from the ERCIM Executive Committee. The Executive Committee takes into account in its recommendation, a brief statement, by those who propose the establishment of the ERCIM working group, on the group's scientific goals and plans including a tentative list of its members. An ERCIM member institute can withhold or delay its participation to an ERCIM working group. A list of ERCIM member institutes participating in the working group is appended to the minutes of the Board of Directors meeting that approved its establishment.

The activities of a working group can be subdivided into three areas: workshop, project proposals, mobility and fellows.

A working group receives support in the form of initial seed money, on application to the ERCIM Executive Committee, to set up a first workshop. Workshops are open to any researcher in the field.

Travel support is given to ERCIM researchers by their institutes to participate in the workshops organized by the group provided they align with the half-year ERCIM meetings. It is expected that each working group organizes at least one annual workshop.

A major activity of any ERCIM working group is to actively search for project funding that crosses the national borders. Support is given by the ERCIM office to the chairman of the working group or a person designated by the chairman. This support can cover travel and subsistence of the chairman or the designated person, for up to two meetings that take place in Europe. The objective of the meeting has to be the preparation of a project proposal, where at least three ERCIM member institutes participate as associate partners to ERCIM-EEIG and ERCIM-EEIG participates as partner or coordinator.

Participants to the proposal preparation have to inform the chairman of the working group, whether, to the best of their knowledge, any proposal, similar in content, with their involvement or with the involvement of any of the partners in the consortium, is being submitted to an EU research program.

A working group is also the focus of internal mobility within ERCIM. ERCIM institutes have reserved resources to stimulate mobility, so as to work on collaborative research projects from 1-6 months. Workgroups will also be invited to identify topics of interest to be included in the half-year calls for fellows.

Finally, the working group leader maintains the web page at the ERCIM server with a synopsis of its charter, members, and upcoming events.

A working group can cease being designated an ERCIM working group and therefore lose the benefits associated with its official recognition as such, if the working group so decides and notifies the BOD, or if the working group ceases all its activity for a period of two years.