It was reported by the French media on 26 January 2009 that he joined Premier League team West Bromwich Albion on a trial basis. On 2 February 2009, the January transfer deadline day, he joined them on loan with a view to a permanent deal at the end of the season. Mulumbu's first term at The Hawthorns was interrupted by injuries and he had to wait until April to make his Premier League debut, coming on as a sub in a 2–2 draw at Portsmouth. He signed for West Brom permanently on a one-year contract for a fee of £175,000 on 10 July 2009.