The Blues move up to third in the Premier League with a comfortable victory over their London rivals as the midfielder hits 200 goals and Eden Hazard secures the points
The veteran midfielder is now two goals behind Bobby Tambling's all-time club record after reaching the landmark against his former side with a 19th-minute header to put the Blues in front.
Eden Hazard capped a brilliant individual performance with Chelsea's second on 49 minutes as Rafa Benitez's side took advantage of Tottenham's defeat to Fulham to move up to third in the Premier League table.
The result leaves Chelsea in position for a strong finish to a turbulent season as they target a top-four place, while they are also in the last eight of the FA Cup and the Europa League.
Against a timid West Ham side, they played with flair and energy, with the visitors particularly unable to handle the vision and trickery of Hazard and Juan Mata as the attacking duo floated in to pockets of space.
The major talking point before kick-off was Benitez's decision to drop John Terry and Fernando Torres to the bench despite both players scoring in Thursday's Europa League win over Steaua Bucharest.
West Ham made two changes to the side who beat Stoke City as Jack Collison and Ricardo Vaz Te came in to the team, with Joe Cole unable to recover in time from a hamstring problem to face his former side.
The hosts started brightly and should have taken the lead after just six minutes when Lampard played Demba Ba through on goal but the striker woefully miskicked his shot off target as he looked to place the ball in the corner.
Lampard, however, had no such problem in the 19th minute as he netted his 11th league goal of the campaign. The midfielder drifted in between the West Ham defenders and was perfectly placed to head Hazard's clipped pass in to the net from eight yards.
The only frustration for Chelsea at the break would have been their failure to double their advantage, with Ba guilty of missing their best opportunity when he shot straight at Jussi Jaaskelainen after again being played in one-on-one with the Hammers goalkeeper.
But less than five minutes after the re-start, the second goal arrived - and in emphatic style. Hazard played a delightful one-two with Juan Mata, danced across the West Ham penalty area and, after fooling three defenders by faking to shoot, slammed the ball in to the bottom corner with his left foot.
With the victory seemingly secure, Chelsea cruised to full-time with fluid possession-based football and more sparks of genius from Hazard and Mata. A job well done.