This is the second loss for the ruling Congress in a span of one month after it lost badly in the Garo tribal council elections held last month.
HSPDP candidate Diostar Jyndiang won the bye-election by a margin of 2,763 votes over rival Congress candidate Gabriel Wahlang to retain the seat held by its former president for a very long time.
While Jyndiang secured a total of 11,179 votes, Congress candidate secured a total of 8,416 votes.
The ruling Congress also lost badly in the Garo tribal autonomous council elections last month winning only seven of the 29 seats they contested even as the NDA allies, the National People's Party (NPP), claimed maximum seats to form the executive committee.
In the Meghalaya Assembly, the ruling Congress has 30 members, the UDP has eight, the HSPDP four while NCP and NPP have two members each. The rest are Independents.