PURPOSE: This study describes the prevalence of religious and/or spiritual (R/S) struggle in long-term young adult (YA) survivors following hematopoietic cell transplantation (HCT) as well as existential concerns (EC), social support, and demographic, medical, and emotional correlates of R/S struggle. METHODS: Data were collected as part of an annual survey of survivors of HCT aged 18-39 years at survey completion; age at HCT was 1-39 years. Study measures included measures of R/S struggle (defined as any non-zero response on the negative religious coping subscale from Brief RCOPE), quality of life (QOL), and depression. Factors associated with R/S struggle were identified using multivariable logistic regression models. RESULTS: Fifty-two of the 172 respondents (30%), who ranged from less than a year to 33 years after HCT, had some R/S struggle. In bivariate analysis, depression was associated with R/S struggle. In a multivariable logistic regression model, individuals with greater EC were nearly five times more likely to report R/S struggle. R/S struggle was not associated with age at transplant, time since transplant, gender, race, R/S self-identification, or medical variables. CONCLUSION: R/S struggle is common among YA HCT survivors, even many years after HCT. There is a strong correlation between EC and R/S struggle. Given the prevalence of R/S struggle and its associations with EC, survivors should be screened and referred to professionals with expertise in EC and R/S struggle as appropriate. Further study is needed to determine longitudinal trajectory, impact of struggle intensity, causal relationships, and effects of R/S struggle on health, mood, and QOL for YA HCT survivors.