GATS stands for General Agreement on Trade and Services. This is a treaty under the control and part of the WTO .

The GATS defines four modes of trade in services. Mode 4 refers to the temporary migration of workers, to provide services or fulfill a service contract. Because the current framework of Mode 4 allows for only temporary movement of workers across borders to provide services, and their visa as well as their right to stay and work are tied to their original terms of employment or contract and to their employer.

The WTO is basically negotiating a global guest worker program.