The popularity of tattoos is burgeoning with 20-30 million tattooed individuals in the Western World. Requests for removal can be expected to rise concurrently with increased applications. Laser removal of tattoos is potentially a more cosmetically acceptable method of removing tattoos than surgical excision or dermabrasion. Nevertheless, complications and side-effects can result from laser treatment and include scarring, hypopigmentation, hyperpigmentation, partial removal, infection, bleeding and tattoo ink darkening. The latter has been reported for flesh-toned and red tattoos. Such a complication has never been reported for the laser treatment of a yellow tattoo in the dermatological literature. We describe a case of tattoo ink darkening of a yellow tattoo after treatment with the 532 nm quality-switched Neodymium : Ytrrium-Aluminium Garnet laser to highlight clinicopathological features. The mechanism by which some tattoos darken after laser treatment is not clearly understood. We review darkening of tattoos after laser treatment to raise awareness of this important complication. This paper will help to facilitate discussions with the patient and in obtaining informed consent prior to commencing treatment. Tattoo ink darkening of a yellow tattoo adds to the growing list of complications resulting from attempts at tattoo removal.