By comparison, growth across the region was 6.1 percent last year.
Inflation in 2022 will reach 7.5 percent after 3.6 percent in 2021, the bloc said.
Ivorian President Alassane Ouattara, speaking after a summit in the country's economic capital Abidjan, said WAEMU members had not been spared from "the deep crises which are affecting the entire world."
He pointed to the impact of the war in Ukraine, the "shock" of the Covid pandemic and a "worrying" security situation regionally.
WAEMU comprises Benin, Burkina Faso, Guinea-Bissau, Ivory Coast, Mali, Niger, Senegal and Togo, gathered under a 1994 treaty to build an integrated economic space in West Africa.
Three WAEMU countries -- Burkina Faso, Mali and Niger -- are wrestling with a bloody jihadist insurgency that threatens also to spread southwards, towards Benin, Ivory Coast and Togo.
Part of spending that should have gone on health and education is now having to be diverted to "defence and security", Ouattara said.
The Abidjan talks came a day after a summit in the Nigerian capital Abuja of members of a wider West African bloc, the 15-nation ECOWAS, which deals with political and security policies.
Its leaders on Sunday agreed to create a regional force that would intervene at times of crisis, "whether this is in the area of security, terrorism or to restore constitutional order in member countries," in the words of the president of the ECOWAS commission, Omar Alieu Touray.
Since August 2020, Mali and Burkina Faso have each experienced two coups triggered by anger within their militaries over the insurgency.
There has also been a government overthrown in Guinea, but which was caused by a domestic political crisis.