The 24 year-old DR Congo international has decided to focus his energies on success with the Baggies.
He won the first of his 12 caps in 2008 but has decided not to continue on the international stage in order to focus on his club career and for family reasons.
"This decision has been taken following long discussions with my family and medical advisers," Mulumbu said on wba.co.uk.
"I hope to have the opportunity to extend my professional career which is the guarantee for my family's security, by retiring from international commitments.
"It was an extremely hard decision for me to take, but I wish DR Congo and the whole team great success."