The effects of caregiving on mothers of adults with intellectual disability was examined by determining whether there are differences in quality of life and related factors between mothers with different employment status. Study participants were 302 working-age mothers who had adult children with intellectual disability based on the 2008 census survey on intellectual disability carried out in Hsinchu, City, Taiwan. Results revealed that nonemployed mothers are more likely to have a lower level of health status, including the WHOQOL Physical Health domain, than are mothers employed fulltime. Multiple regression analysis showed that mothers' quality of life was significantly determined by the availability of a person with whom they could share care work, family income, social support, and employment status.