A federal court ruled in favour of the Australian government worker, who was hurt by a glass light fixture in her hotel room, stating that the injury occurred during her "course of employment".
The woman's barrister argued that the sex was "an ordinary incident of life" in a hotel room, along the same lines as showering and sleeping, according to news.com.au.
The woman, who cannot be named, was sent by her employer to a country town on business in 2007.
She arranged to meet a male friend who lived nearby. After the pair had dinner, they returned to the woman's motel room and had sex, during which she was injured by a light fixture that fell from the wall above the bed.
The judge ruled that "if the applicant had been injured while playing a game of cards in her motel room she would be entitled to compensation".
The fact that she was having sex rather than "some other lawful recreational activity" made no difference to the result.
The male friend said in a statement: "I think she was on her back when it happened but I was not paying attention because we are rolling around."