Peter and Birgitt Weismantel adopted 12-year-old Oscar from the Cats Protection charity at Christmas.
But as he started to settle in at their home in Gordon Avenue, Southampton, he started bringing home his stolen haul.
In recent weeks he has brought home about 70 items leading his owners to inform the police.
Mr Weismantel, 72, said Oscar first started bringing home gardening gloves but quickly moved on to ladies knickers, socks and children's underwear.
As the haul built up his owners became concerned that neighbours would think there was a thief operating in the area so Mr Weismantel contacted police to tell them about his pet's anti-social behaviour.