Chief Minister Lal Thanhawla, seeking a fifth term, was leading in both Serchhip, his home turf, and Hrangturzo.
Congress candidates were also leading in Tuivawl, Tawi, South Tuipui, Hachhek and Tuichawng.
The Mizo National Front (MNF) nominee L. Thangmawia was leading in Lengteng seat where Forests Minister H. Rohluna of Congress was trailing.
The Congress and the opposition Mizoram Democratic Alliance had contested all the 40 seats.
MDA constituents, MNF contested 31 seats, Mizoram People's Conference 8 and Maraland Democratic Alliance one.