The life span and survival parameters of the common marmoset (Callithrix jacchus) in a breeding colony at CLEA Japan, Inc. were investigated. The average life span of male marmosets was 148.5 ± 6.1 (mean ± SE) months of age (M), which was significantly longer (P < 0.01) than that of females (111.7 ± 6.0 M). Additionally, the male population reached 25-, 50-, 75- and 90 %-mortality at an older age than the female population. However, the maximum life span in males (259.9 M) was shorter than in females (262.5 M). The survival of females shows a relatively continuous decline; however, the male marmosets show a slight decline in survival during the first 7-9 years and then a dramatic decrease and another slight decline after 14-16 year of age in survival, i.e., a lifespan curve similar to what is observed in colonies of aging rodents and humans. The sex-associated difference in life span was caused by reproductive burden on the females. The present study reported a longer than expected life span of the marmoset, and a long-lived animal can be a powerful model for senescence and longevity sciences.