Cell proliferation and cell death are two opposing sides of the same coin. The development and homeostasis of multicellular organisms requires the accurate control of both processes. The death that occurs normally as a process of development is called 'programmed cell death' or 'apoptosis'. The phenomenon of developmentally programmed cell death has been known for more than 100 years, but it is only in the last decade that its molecular mechanisms have begun to be uncovered. The nematode Caenorhabditis elegans is one of the few experimental systems in which a genetic approach is available to dissect the processes of programmed cell death, and in fact, findings from studies using C. elegans have already played a very important role in elucidating these mechanisms. Here, we summarise the progress to date in understanding how cell death is controlled in C. elegans, and review the main machinery of programmed cell death/apoptosis with respect to its evolutionary conservation between C. elegans and other species.