The Montgomery County D.A.'s office says, between August 4th and October 19th, Chheng Ploysy of Lansdale met with detectives five times.
On three of those occasions, he was accompanied by the little boy.
Photos released by the D.A. allegedly show Ploysy riding a bicycle during one of the deals, with the boy inside a safety trailer.
The last undercover drug deal was on October 19th, the D.A. said, when Ploysy was arrested.
Police say they believe he was distributing marijuana for re-sale.
Ploysy is facing numerous drug charges and charges of endangering the welfare of a child.