She was also made Minister for Women and Equalities.
Her predecessor at the DWP, Esther McVey, also made a ministerial return in the Housing and Planning Department, she will also attend Cabinet.
Meanwhile Sajid Javid has replaced Philip Hammond as Chancellor of the Exchequer.
Ms Rudd tweeted: “Thrilled and honoured to be reappointed to the @DWP and also take on @WomenEqualities.
“I look forward to continuing my work to improve the welfare system and I’ll do everything I can to help women and girls improve their lives.”
Mr Javid also took to Twitter in response to his appointment, he wrote: “Deeply honoured to be appointed Chancellor by PM @BorisJohnson.
“Looking forward to working with @hmtreasury to prepare for leaving the EU, unifying our country and priming our economy for the incredible opportunities that lie ahead.”