About 7.5m cats are kept in households throughout the UK, compared with 6.1m dogs, according to the charity Cats Protection League.
This compares with 4.9m feline households in 1979.
In a survey by the charity, nearly 40% of people named cats as their favourite pet - with just 7% preferring dogs.
The charity said that as lifestyles change, becoming increasingly urban and busy, so do people's ideas of a perfect pet.
The research said 57% of people liked cats because they were affectionate, 49% liked them for their independence and 46% preferred them because they were clean.
Nearly a quarter of people kept a cat because they were low maintenance, and 27% said they liked not having to exercise them.
Cats were most popular with the 35-44 age group - with nearly a third of all people in this group owning one, while dogs were preferred by older people.
Preferred partners
The survey also threw up several strange statistics.
Nearly two-thirds of cat owners said curling up with their pet was the best way to beat stress - preferring that to speaking to a friend or going for a drink.
Almost half of both men and women said they would rather wake up with their cat than their partner.
And 98% of women said they would rather date someone who liked cats, than someone who did not.