This study was performed to identify the patterns and mechanisms of the development of personal strength of bereaved older adults over a 4-year period after spousal death. The findings showed that while bereaved older adults, on average, experienced a moderate level of personal strength at 6 months post-spousal death with a slight increase over a 4-year period, there was a significant individual difference in the level of personal strength at 6 months post-spousal death. Finding meaning was a crucial factor influencing interindividual differences in personal strength at 6 months post-spousal death, mediating between social support and personal strength as well as caregiving strain and personal strength. Having higher religiosity was directly associated with a higher level of personal strength. (Contains 2 tables and 1 figure.)