The actinobacteria have been detected in guts of many animals including insects by molecular methods. Finding novel actinobacterial species, screening novel natural products, reevaluation of coevolution between attine ants and actinomycete bacteria, and eliminating the parasites of disease vectors have been done based on the studies on animal symbiotic actinobacteria. The present results for terrestrial animal symbiotic actinobacteria were reviewed and the perspectives were outlined.