Abstract: A light bulb cooling jacket is adapted to confine a light bulb in a space through which cooling liquid, such as water, may be circulated. The light bulb cooling jacket includes an shell having a rim, the rim defining an opening in the shell. A stopper fits in the opening in the shell and seals against the rim of the shell. The stopper has an aperture in it. The aperture is adapted to receive a portion of a light bulb, which is held and sealed in place in the aperture. The means employed to hold the bulb in place is adapted to engage a generally cylindrical portion of the light bulb, such as the neck of a standard 1000 W bulb. An important characteristic of the present invention that follows from this construction is that the light bulb cooling jacket may be used with a variety of standard high intensity light bulbs. Ports are provided in the stopper for introducing and withdrawing cooling liquid from the space enclosed by the shell and the stopper.