The Hammers are enjoying another good season under David Moyes and currently occupy fourth spot.
However, United are just one of a number of chasing teams and, if we successfully complete a league double over the Londoners at the weekend, we will leapfrog West Ham in the table.
Here's everything you need to know ahead of another important game...
HOW CAN I FOLLOW THE MATCH?
The game at Old Trafford kicks off at 15:00 GMT on Saturday, so it will not be broadcast live in the UK. MUTV's coverage will begin when Matchday Live goes on air at 13:55 GMT - the show will include pre-match build-up, live match radio commentary and post-match analysis.