Lilo's Experiment Book is a log book/scrapbook seen in the Lilo & Stitch: The Series episodes "Drowsy" and "Snafu", as well as in Leroy & Stitch. The book has a small notepaper taped to the cover that says Cousins. Lilo keeps a record of every rehabilitated experiment in this book with a photo showing each experiment, and the one true place they belong. At the end of Leroy & Stitch, a group photo of all the experiments in Lilo's extended ʻohana can be seen.
- Lilo keeps the book under her pillow on her bed.
- In Leroy & Stitch, Lilo took a picture of Stitch after deciding to let him be captain of the B.R.B. 9000.
- When a Leroy clone discovers the book and hunts down the experiments, he cuts the photo of said experiment he captures (including the one with Mertle and Gigi) by crossing an "X" onto it with his claw, thus destroying said photo.
- Stitch's photo is the only one that hasn't been scratched out, given that he, along with Jumba and Pleakley, were sent off to a black hole.
- At the end, a group photo was taken with Lilo, Stitch, Nani, David, Jumba, Pleakley and all the experiments.
- There were two errors in the group photo. Backhoe appeared twice: one visible on the rooftop, and the other visible on the stairs. Additionally, Phoon was shown twice: one in her normal form on the rooftop, and one in her mutated form on the porch.
- Mertle was in the photo since Gigi wanted to be in the shot.
- Reuben, 627 and Leroy are the only experiments that haven't had their photo taken in the book.
- Reuben was with Gantu the entire time, and after Gantu was reinstated as captain, Reuben was given a spot to be his galley officer.
- Since the experiments created before Stitch had been rehabilitated, it would be obvious for 627 and Leroy to not appear, as they couldn't be rehabilitated.
- In the group photo, some of the experiments were not present.