The objective of this study is to evaluate the effects of chromic chloride (CrCl3) on chick embryo fibroblast (CEF) viability.The cells were incubated with CrC13 (0.02, 0.1, 0.5, 2.5, 12.5, and 62.5 μM), and the viability was determined using MTT assay, morphological detection and flow cytometry.The results show that lower concentrations of CrCl3 (0.02, 0.1, and 0.5 μM) did not damage CEF viability.At 0.1 μM, CrCl3 can increase CEF viability (P<0.05).However, at higher concentrations of CrCl3 (2.5, 12.5, and 62.5 μM), the number of apoptotic and necrotic cells (P<0.01) and intracellular reactive oxygen species (P<0.01) increased.In addition, decreased mitochondrial membrane potential (P<0.01) and enhanced intracellular calcium levels (P<0.01) were observed after the exposure.Moreover, apoptotic morphological changes induced by these processes in CEF were confirmed using Hoechst 33258 staining.Cell death induced by higher concentrations of CrC13 was caused by an apoptotic and a necrotic mechanism, whereas the main mechanism of oxidative stress and induced mitochondrial dysfunction was apoptotic death.The induced apoptotic death in CEF is concentration-and time-dependent.