Support of parents of children with cancer requires healthcare personnel to be knowledgeable about the prevalence of post-traumatic stress symptoms among Iranian parents of children with cancer. This study was conducted to fulfill this aim in the South-East of Iran. Using the Impact of Event Scale -Revised, for parents of children with cancer, 200 parents in two hospitals supervised by Kerman University of Medical Sciences, were assessed. The total mean score of post-traumatic stress symptoms was 41.70. Among all categories of the Impact of Event Scale -Revised, the highest mean belonged to the category of 'intrusion' 16.03 (SD = 6.24) and the lowest one belonged to the category of 'hyperarousal' 10.68 (SD = 4.58). Based on the results, mothers had higher post-traumatic stress symptoms compared with fathers (p < 0.05). Adjusted odds ratio showed that the prevalence of post-traumatic stress symptoms among mothers was 2.49 times more than that among fathers (p = 0.01). There was no association between sociodemographic data and post-traumatic stress symptoms. More research is needed to elucidate the Iranian parents' experience of having children with cancer.