Thabane formed his new party after walking out of cabinet in October. His ABC party has pursued a populist agenda, with promises to work on poverty and corruption.
The LCD has gained most of the constituency seats available, with another 40 proportional representation seats available to smaller parties to make up the country's 120-seat parliament.
The party won 77 seats at the last elections in 2002. However, its majority was reduced when Thabane led a group of 17 MPs to sit on the opposition benches.
Thabane has already voiced grievances about the electoral process, raising the possibility of a contested ballot.
He said some of his supporters had found their names absent from the electoral register and alleged there had been some multiple voting.
Observers from the Southern African Development Community (SADC) acknowledged that there had been some minor problems, but gave the vote a generally clean bill of health on Sunday.
John Chiligati, SADC mission chief, said: "In spite of these shortcomings, it is our opinion that the mission can ... confidently say congratulations to the people of Lesotho following the holding of credible, peaceful and transparent elections."
The final declaration to the parliamentary election was expected at 12pm (0900 GMT) on Tuesday, with results from the countryside lagging behind those from urban areas.