Election officials in Myanmar have confirmed Aung San Suu Kyi and her National League for Democracy have won at least 40 of the 45 seats being contested in by-elections.
Ms Suu Kyi said she hoped the polls marked the start of a new era in Burma.
She has promised to use her voice to continue to push for further reform.
But the parliament remains dominated by the military and its allies, who hold the majority of the 664 seats.
The by-elections were being held to fill 45 seats left vacant by the appointment of ministers after the polls that formally ended military rule in November 2010.
The NLD was competing in its first elections since 1990 after boycotting the 2010 polls. It was one of 17 opposition parties that took part.