Post-traumatic growth (PTG), depression, and hope have not been adequately studied among elderly cancer patients living in Middle East countries. The aim of the study was to assess these constructs in elderly cancer patients and examine whether depression and hope contributed to variations in PTG among these patients. A sample of 142 Iranian elderly people with Azari ethnicity (55 female, 87 male), with average age of 68.4, diagnosed with cancer who admitted to oncology wards and cancer clinics of Hospital were participated in the study. Study tools included demographic details questionnaire, “posttraumatic growth inventory”, Herth Hope Index (HHI), and Beck Depression Inventory (BDI). Data were analyzed using SPSS-22 software. The means and standard deviations of the PTG, BDI, and HHI scores for all participants were 70.27 ± 12.43, 12.1 ± 6.5, and 34.63 ± 3.13, respectively. The results showed that PTG was negatively correlated with depression (r = −0.60, p < 0.001), and positively correlated with hope (r = 0.50, p < 0.001). All dimensions of the PTG were significantly correlated with total BDI and HHI scores. Depression and hope correlated with some of the variance of PTG in the Iranian elderly patients with cancer. Offering counseling programs and delivering appropriate levels of nursing care may help decrease patients’ depression and increase their hope.