Our study aimed to analyze and compare the grief experiences of individuals in Iran who lost family members to COVID-19 and those who lost loved ones to other natural causes. In this study, telephone interviews were conducted with 640 first-degree relatives, and finally, a total of 395 people remained in the research. Participants answered the Prolonged Grief Questionnaire (PG-13-R) and Grief Experience Questionnaire. The results showed that the most common symptoms and features of grief were feeling guilt, searching for an explanation, somatic reactions, and rejection, with no significant difference observed between the 2 death groups. However, the average scores for these symptoms were higher in the COVID-19 death group. Moreover, the majority of bereaved reported signs and symptoms of prolonged grief, with a higher percentage in the COVID-19 death group, although there was no significant difference between the 2 death groups in terms of the distribution of symptoms and signs of prolonged grief. These findings suggest that the bereavement process can be challenging, and losing a loved one to COVID-19 may lead to more intense experiences of grief. The study reveals high levels of guilt, searching for meaning, somatic reactions, and rejection among COVID-19 grievers. Losing loved ones to the pandemic appears linked to more intense, prolonged grief symptoms.