The longest working prostitutes in Amsterdam, twin sisters Louise and Martine Fokkens, have officially retired — but only after 50 years of work and over 350,000 clients served.

"I was a little bit tired," Louise told As It Happens host Carol Off in an interview that aired March 18.

The sisters said that old age and arthritis were the main reasons for their retirement and have written about their exploits in a new book called The Ladies of Amsterdam.

In a lively and upbeat interview, the twins, who began their careers in their early twenties, explained how they enjoyed their time working in Amsterdam's red light district. They described the place as safe and more fun than working on the streets.

"We like to work in the red light district," said Louise in broken English. "You had fun, we know a lot of people … the American boys, the Canadian boys, the German … every country come there."

The women said they enjoyed spending time with their clients and that they were so successful they have their own house.

But not all memories were pleasant.

Things changed with the European Union and the legalization of prostitution in the Netherlands, said the twins.

At first, women from all over Europe began arriving to work in Amsterdam’s red light district, they said. That's when the "mentality" of relationships between clients and prostitutes began to change for the worse, they said. When prostitution became legal soon after, life as a sex worker further deteriorated because the government began taking some of their earnings.

Asked if they will miss the work, the sisters said they would.

Louise said working makes her feel younger, and Martine said she misses it because it’s sometimes nice to be your own boss.

To hear the complete conversation, including the Fokkens sisters future plans, click the audio button above.