The Morocco striker joins until the end of the season after failing to make an impact on the Arsenal first-team this season.
“I’m very happy to be here, I want to play and give my best for this team,” Chamakh told the official site. “I can bring my heading, some goals and we will see what else.
“I played with Alou Diarra in Bordeaux and we were champions together. I also know Mohamed Diame and Carlton Cole.
“I think this will be a very important move for me and I don’t want to waste any more time. I want to contribute immediately. I didn’t have opportunities to play recently, but I did well before and I know I am a very good striker. We played only one striker at Arsenal, so I didn’t play a lot, so I hope to do so more with West Ham.”