The Blades remained rooted to the foot of the table, after no wins in nine, whilst the Hammers picked up their first away win since October.
The hosts carved out the better chances in the opening exchanges, with George Baldock and Oli McBurnie forcing early stops from Lukasz Fabianski.
David Moyes’ side did grow into the game before the break, as United began to turn the screw, but Tomas Soucek nodded over their best chance.
The Blades continued to have the upper hand after the break, as David McGoldrick tested Fabianksi, but their familiar lack of cutting edge was exposed on the hour.
Oli Norwood lost possession in midfield as Declan Rice slipped in Sebastien Haller outside the box, and the Malian fired an unstoppable effort past Aaron Ramsdale.
That goal knocked some of the life out of Chris Wilder’s team, as West Ham pushed for a second.
And Rice was inches away from securing the game as his header hit the bar on another frustrating afternoon for the Blades.
Full Time at Bramall Lane it’s Sheffield United 0 West Ham 1