The clonogenic cell survival assay determines the ability of a cell to proliferate indefinitely, thereby retaining its reproductive ability to form a large colony or a clone. This cell is then said to be clonogenic. A cell survival curve is therefore defined as a relationship between the dose of the agent used to produce an insult and the fraction of cells retaining their ability to reproduce. Although clonogenic cell survival assays were initially described for studying the effects of radiation on cells and have played an essential role in radiobiology, they are now widely used to examine the effects of agents with potential applications in the clinic. These include, in addition to ionizing radiation, chemotherapy agents such as etoposide and cisplatin, antiangiogenic agents such as endostatin and angiostatin, and cytokines and their receptors, either alone or in combination therapy. Survival curves have been generated for many established cell lines growing in culture. One can use cell lines from various origins including humans and rodents; these cells can be neoplastic or normal. Because survival curves have wide application in evaluating the reproductive integrity of different cells, we provide here the steps involved in setting up a typical experiment using an established cell line in culture.