While filming the sai/sword fight, Jennifer Garner accidentally got her knuckles sliced by Will Yun Lee. She got her knuckles patched up, and when she and Lee resumed, he subsequently sliced her again in the exact same spot.
Although the comic strip Elektra usually wears a pair of large gold hoop earrings as part of her costume, Jennifer Garner did not wear them in the movie. A pair of earrings were provided as part of Jennifer's costume, but she was unable to wear them as they were for pierced ears and she did not at the time have her ears pierced.
The character of Stick was originally introduced in the Frank Miller era of the Daredevil comic book as the man who taught Matt Murdock martial arts and how to control his heightened senses other than serving as Elektra's instructor. All details relating to Stick's connection to the aforementioned character were omitted.
The character Typhoid is based on Typhoid Mary, a villain from the Daredevil comics, though Typhoid's powers of poison are different from Typhoid Mary's psychic abilities of telekinesis and pyrokinesis.
McCabe has no comic book counterpart. However, there was a character named Nina McCabe, first introduced by comic book writer Peter Milligan in the first, short-lived Elektra ongoing series. Nina's father was killed in front of Elektra and Elektra sort of adopted her, becoming her sensei. The character of Nina is pretty similar to Abby.
Due to the low level response from the previous film Daredevil (2003), promotion for this movie claimed ties to the movie X-Men (2000) instead, which had a much higher popularity response. The first promotional mention of ties to the Daredevil movie only took place one week before the Elektra movie was to be released.
A short clip used in the trailers and TV commercials shows a ring of energy emanating from what appears to be the hedge maze that is featured during the final action sequences. This footage does not appear in the US theatrical release.