In the by-election, ruling SKM didn't send its candidate to Martam-Rumtek. Meanwhile, former SKM candidate Sonam Tshering Venchungpa moved to opposition BJP, and SKM supported him. In addition, D. T. Lepcha had already moved to BJP in August. Former ruling SDF participated in the Sikkim Legislative Assembly election as the opposition for the first time in 25 years. Opposition SRP sent its candidate to Martam-Rumtek for the first time. Opposition INC boycotted this by-election.
As the result, Sonam Tshering Venchungpa of BJP defeated his nearest rival Nuk Tshering Bhutia of SDF.