Goalkeeping errors by Robert Green saw Bolton come away from West ham with all three points. Kevin Davies and Gary Cahill pounced on errors by Robert Green to score in the first half and Matt Taylor made sure of the win with a late free-kick after Carlton Cole pulled one back.
Bolton boss Gary Megson said, "We spoke about the way West Ham would come onto us and we had to try and negate that by taking the game to them and playing in their half.
"We've got work rate, resilience and character in spades but today we played some decent football.
"To come to a club that has won its first three games of the season here, to beat them on their home patch is a big thing for us."