The aim of this study was to investigate the psychometric properties of the Persian version of the Inventory Complicated Grief (ICG) including reliability, validity and factorial structure. In this cross-sectional study, 332 women and men bereaved at least 6 months from the adult population of Iran. The results showed Cronbach’s alpha was found to be 0.94 for the scales overall score. Inventory Complicated Grief found a positive and significant correlation between the beck depression inventory (BDI) (r = .62, p < .001) and grief experience questionnaire (r = .74, p < .001). Still, he also found that there was a negative correlation between adult hope scale (r = −.44, p < .001). Furthermore, the results of the EFA result showed four factors on this scale. Overall, ICG showed good reliability and validity in Iranian population and it could be applied for assessing their Complicated Grief.