Inflammatory activation of astrocytes has been implicated in various neurodegenerative diseases. The elimination of activated astrocytes by apoptosis or the deactivation may be the mechanisms for auto-regulation of activated astrocytes. To test the possibility of apoptotic elimination of activated astrocytes, we examined a potential correlation between activation state of astrocytes and their viability using C6 rat glial cells and rat primary astrocyte cultures exposed to a variety of inflammatory stimuli such as lipopolysaccharide, interferon-gamma, and tumor necrosis factor-alpha. Nitric oxide production was measured to evaluate inflammatory activation of astrocytes. We found that: (i) the activation of astrocytes by the combination of lipopolysaccharide and inflammatory cytokines, but not by either alone, led to nitric oxide production followed by apoptotic cell death; (ii) the amount of nitric oxide produced by activated astrocytes was inversely proportional to the viability of the cells; (iii) inhibition of nitric oxide synthase by N-monomethyl L-arginine blocked death of activated astrocytes; and (iv) nitric oxide donors induced apoptosis of astrocytes in a caspase-dependent manner. Taken collectively, our results suggest that activated astrocytes produce nitric oxide as an autocrine mediator of caspase-dependent apoptosis, and this type of programmed cell death of astrocytes may be the underlying mechanism for the auto-regulation of inflammatory activation of astrocytes.