Goals from Nathalie Björn, Mayra Ramírez, Johanna Rytting-Kaneryd and substitute Catarina Macario at King Power Stadium handed Leicester only their third defeat since the New Year, as they remain seventh in the WSL standings.
Willie Kirk made just one change to the starting XI that beat Bristol City before the international break, with Courtney Nevin coming in to replace the injured Shannon O'Brien.
The first whistle announced a milestone achievement for one of our Foxes, Sam Tierney, as Sunday's action was her 100th appearance in Leicester colours, and she becomes the first women's player to reach the landmark for the Club.
Chelsea looked dangerous from the off, with winter signing Ramírez looking strong, but the home side were creating chances themselves, coming closest when Jutta Rantala fired an effort into the gloves of Hannah Hampton after being played in by Tierney.
The next big chance in the match came when Yuka Momiki hit the post from close range. Rantala once again tested Hampton before the Japanese forward picked the ball up inside the box, but only managed to see her low effort glance off the upright and stay out.
Five minutes from the break, the visitors broke the deadlock from a corner when Björn managed to lift the ball over Lize Kop and past Josie Green who desperately jumped to try and head it over.
Right before the interval, the Blues doubled their lead when Julie Thibaud was dispossessed high up the pitch by Ramírez who drove clear, rounded Kop, and slid the ball into an empty net in front of the travelling fans.
The first chance that came following the restart fell for Momiki, who could only find the Chelsea 'keeper after being played in by Tierney and cutting onto her right-foot to take aim from the edge of the box.
Little over the hour mark, Chelsea has a third through an unfortunate deflection. Rytting-Kaneryd had space on the right wing, cut inside and fired an effort towards goal, which clipped Janice Cayman on the way through, unsettling Kop.
As the game drew to a close, City looked to be running out of steam, to which Chelsea took advantage and scored a fourth when substitute Macario fired low under the Leicester 'keeper from inside the penalty area.
One silver lining for the Foxes was the return of German striker Lena Petermann, who got her first minutes on the pitch since returning from injury and will be crucial throughout the remainder of the season as Leicester prepare for an Adobe Women's FA Cup Quarter-Final clash against Liverpool up next.