The Question:

What is the longest-running soap opera?

The Answer:

Guiding Light, previously known as The Guiding Light, which has aired on CBS since June 30, 1952. Furthermore, it is the only television soap opera to have started as a radio show. The radio version aired on NBC, starting on January 25, 1937. Counting the radio years, Guiding Light is the longest-running show in broadcast history.

—The Fact Monster