The C. elegans hermaphrodite, a simple nematode (roundworm), has 302 neurons, the morphology and connectivity of which have been completely mapped, providing an opportunity for complete and rigorous understanding of the neural basis of behavior. Using tightly-focused pulses from an ultrafast laser, we can ablate regions of biological tissue with submicron precision. It is thus possible to snip individual nerve fibers with minimal collateral damage. The application of femtosecond laser surgery to this model organism allows the precise dissection of simple neural behavioral circuits as well as the study of neural regeneration in vivo. Combined with optical neurophysiology, quantitative behavioral analysis and the powerful genetic methods of C. elegans, these biophysical techniques are creating new opportunities in the study of neural function and regeneration at the molecular, cellular and circuits level.