The production number of this episode is B-503. While this was the first episode broadcast and clearly intended as such, it was third in production order.
The costume worn by Booth Colman is the same one that was worn by Maurice Evans in both Planet of the Apes (1968) and Beneath the Planet of the Apes (1970).
This is the only episode in which Roddy McDowall (Galen) and Booth Colman (Dr. Zaius) share a scene.