Pro-tem Speaker Ninong Ering administered the oath of office to the newly elected members during the opening day of the two-day special session convened by Governor Lt Gen (Retd) K T Parnaik.
Out of 60 MLAs, 59 took their oaths during the day, with Ering having been sworn in by the Governor the day before.
There are 20 new members in the current assembly.
In the April 19 polls, four women candidates were elected to the assembly.
Ering, in his congratulatory remarks, urged the elected members to perform their duties with dedication, to uphold the traditions of the House and meet the expectations of the people.
The House also held a two-minute silence in memory of all former members who have passed away.
The elections for the Speaker and Deputy Speaker are scheduled for Saturday.
In the 60-member House, the ruling BJP secured 46 seats, the National People’s Party (NPP) won five, and the Ajit Pawar faction of the Nationalist Congress Party (NCP) obtained three seats.
The People’s Party of Arunachal (PPA) won two seats, the Congress secured one, and there are three Independent MLAs.