Chavan's sister-in-law Seema and father-in-law's brother Madanlal are members of the plush 31-storey Adarsh building in south Mumbai.
Earlier on June 30, Chavan himself had deposed before the commission.
The commission is likely to record Seema and Madanlal's statements on how they became members of the society and the mode of payment towards the flats.
During his tenure as the state Revenue Minister in 2000 and then the Chief Minister in 2009, Chavan had dealt with the files pertaining to the Adarsh society.
Chavan has been named as an accused by CBI in its probe in the scam. Chavan, who had to step down from the post of chief minister after the scam came to light, is accused of showing undue favours to the society in return of procuring flats for his family members.
CBI in its chargesheet had alleged that Chavan misused his official position twice