Miliaria crystallina is due to obstruction of the eccrine sweat duct as it courses through the stratum corneum. Miliaria crystallina consists of superficial, subcorneal, and noninflammatory vesicles. Ultraviolet light exposure, resident organisms on skin, and repeated sweating episodes are considered as facilitating factors. Ultraviolet phototherapy with narrowband ultraviolet B (NBUVB) has been known to have a beneficial effect on various skin diseases. It may be considered to be an alternative for generalized pruritus patients, especially if they are resistant to standard treatments. Herein, we present a case of adult miliaria crystallina due to artificial ultraviolet radiation for phototherapy. Although it is underestimated for self-limited disorder and short duration, we should keep in mind that NBUVB phototherapy commonly used in dermatology may cause a miliaria crystallina.