NEW YORK (CNN) -- "Guiding Light" will go dark in September after 72 years and 16,000 episodes, CBS announced Wednesday.

Gina Tognoni is one of many performers who have appeared on "Guiding Light" over the years.

The daytime soap opera's declining viewership led to the decision, according to a CBS spokeswoman.

The show, which the Guinness Book of World Records lists as the longest-running television drama, first aired on NBC radio in 1937 as a 15-minute serial, the spokeswoman said. It moved to television on the CBS network in 1952.

The last episode is set to air on September 18, she said.

The show is produced in New York.