Lampard's two goals, which included a penalty, came either side of an Oscar strike at West Ham's Upton Park ground, with Jose Mourinho's side now level on points with second-placed Liverpool after this victory.
The gulf in class between the two London clubs was apparent throughout and only goal difference is currently keeping West Ham out of the bottom three.
West Ham had to defend stoutly early on as Eden Hazard's cross from the left narrowly evaded Branislav Ivanovic and James Tomkins, the centre-back, did well to dispossess Samuel Eto'o after the ball had been played to the Chelsea forward in the box.
Oscar could not hit the target from the edge of the penalty area after Ravel Morrison had lost possession but West Ham replied with a move that saw Kevin Nolan put the ball in the net only to be penalised for an obvious barge on goalkeeper Petr Cech.
The right-back's miscued his attempt to play the ball back to Jussi Jaaskelainen and the goalkeeper could not stop himself from bringing Oscar down.
Lampard blasted the penalty high into the net in the 21st minute to record his first goal in 11 Premier League games, ending his longest barren run for a decade.
England midfielder Lampard headed another chance narrowly wide before Oscar doubled the lead in the 34th minute, with the Hammers' defence again culpable.
Hazard's flick sent the Brazilian away down the middle and when no challenge came in Oscar slotted low past Jaaskelainen from the edge of the box.
West Ham manager Sam Allardyce, who again chose not to field a recognised striker, reacted by making a double substitution five minutes before half-time.
Joe Cole and Jack Collison were taken off, with Modibo Maiga and Mohamed Diame coming on.
Chelsea continued to dominate, however, and Jaaskelainen pulled off an acrobatic save to stop Eto'o from making it 3-0.
England centre-back Gary Cahill almost scored the third early in the second half when but Mark Noble kicked his header from a corner off the line.
Cesar Azpilicueta, playing at left-back instead of Ashley Cole, started a move in his own half that saw him cross to Oscar at the back post only for the midfielder to fire wastefully wide.
Eto'o saw a curling long-range effort drop just miss the target before West Ham spurned an opportunity to get back into the game.
Demel was the man who created the chance with some trickery on the right but when he squared the ball for Maiga in front of goal the substitute could only poke wide.
It proved to be crucial as Lampard made it 3-0 in the 82nd minute with a low, first-time effort after Hazard's initial shot had bounced off a defender.
Substitute Demba Ba, another former West Ham player, put the ball into the net in stoppage time but the 'goal' was ruled out for offside.