Pompeo and his wife asked employees in the Office of the Secretary to carry out tasks such as "picking up personal items, planning events unrelated to the Department's mission, and conducting such personal business as pet care and mailing personal Christmas cards," the State Department's Office of Inspector General (OIG) said in the report, which was published on Friday.
Pompeo served former Republican President Donald Trump's last secretary of state until January 20, when the winner of the 2020 disputed election, Joe Biden, a Democrat, sworn in as the new US president.
The finding is a blow for Pompeo who is seen as among a few of Republicans planning to run for the 2024 presidential election.
"The Pompeos made over 100 requests to employees in the office of the secretary to conduct work that appeared to be personal in nature," found the investigation, which was launched in October 2019 in response to a complaint that Pompeo and his wife were misusing State Department’s funds for personal purposes.
According to the report, Susan Pompeo also once requested an aide to make two hair salon appointments for her. On another occasion, an under secretary of state appeared to help the Pompeos' son secure a discount for a hotel room.