This paper describes a low-cost system for in situ visualization and photoablation of single neurons. The system includes a fiber optics light source equipped with a filter port, a blue excitation filter and a yellow barrier filter, and a light guide which terminates with a focusing lens. This system is inexpensive, easy to use, and requires minimal maintenance. Given its price, this system is readily accessible and has the potential of becoming standard equipment for in situ visualization and killing of individual neurons.