Mitochondria have been shown to play an important role in apoptosis using mammalian cell lines. However, their role in insects is not fully understood; thus, more indepth studies of insect cell apoptosis are necessary. The present study investigates mitochondrial involvement duringConidiobolus coronatus-induced apoptosis inGalleria mellonellahemocytes. Previous research has shown that fungal infection could induce apoptosis in insect hemocytes. Our findings indicate that mitochondria undergo several morphological and physiological changes during fungal infection, e.g., loss of mitochondrial membrane potential, megachannel formation, disturbances in intracellular respiration, increased nonrespiratory oxygen consumption in mitochondria, decreased ATP-coupled oxygen consumption and increased non-ATP–coupled oxygen consumption, decreased extracellular and intracellular oxygen consumption, and increased extracellular pH. Our findings confirm thatG. mellonellaimmunocompetent cells demonstrate Ca2+overload in mitochondria, translocation of cytochrome c-like protein from mitochondrial to cytosol fraction, and higher activation of caspase-9-like protein afterC. coronatusinfection. Most importantly, several of the changes observed in insect mitochondria are similar to those accompanying apoptosis in mammalian cells, suggesting that the process is evolutionarily conserved.