Founded in 1974, ITA has 52 Member Nations and 284 Affiliate Members.

The aims of the ITA are:

- to encourage the use of the subsurface for the benefit of public, environment and sustainable development

- to promote advances in planning, design, construction, maintenance and safety of tunnels and underground space, by bringing together information thereon and by studying questions related thereto.

The Association fulfils its mission:

- by interchange of information among its several Adhering National Organisations

- by holding Executive, Public or other meetings at intervals

- by organising and co-ordinating studies and experiments

- by publication of proceedings, reports and documents