When planning for this tokusatsu show, Toei producer Shirakura thought about where the Den Liner would travel, but was limited by the filming locations that had been standard for many years. So he was left with 3 options: 10 years in the past, a spiritual world or a parallel world. The spiritual and parallel world ideas were shelved and later used for Kamen Rider Wizard & Decade.
It is the first Kamen Rider installment to actually have a combined mecha crossover with a Sentai franchise, Ressha Sentai ToQger.
Due to health problems resulting from being overworked, Yuriko Shiratori known as Hana was forced to drop out of the Den-O's production, forcing the writers to turn her character into a child and replace her with Tamaki Matsumoto for the remainder of the franchise.
Due to the difficulty in bringing Takeru Satoh in to reprise his role as Ryotaro, Momotaros is frequently used to represent Kamen Rider Den-O instead of Ryotaro when Den-O's presence is required in post-series appearances.
The first Rider series to have an anime spin-off series (Imagin anime).