Fear of child disease relapse in parents is the result of mental trauma and by itself is a traumatizing factor. The objective is to study fear of disease relapse in parents of childhood cancer survivors. Methods. We examined 29 parents of childhood cancer survivors. Group 1 consisted of 14 (48 %) parents with children undergoing in-patient treatment for cancer; group 2 included 15 (52 %) parents of childhood cancer survivors who were in remission. Clinical, psychological and experimental methods and techniques encompassed the Hospital Anxiety and Depression Scale (HADS), a measure of an individual’s tolerance to ambiguity (MSTAT-1) and specific measures for child-parent emotional interaction. Results and Discussion. Fear of child’s cancer relapse is identified in parents at the stage of child’s disease treatment, as well as remission; however, the triggers of parental fear of relapse are different. Severity of the parental fear of relapse depends on the parent’s individual personality, in particular susceptibility to anxiety and tolerance to ambiguity. Parents of childhood cancer patients show impaired self-esteem, which is especially evident by the Accepting Oneself as a Parent parameter. Conclusion. Psychological assistance is required by both the parent and their ailing child. Professional psychological assistance should be available to parents throughout the child’s treatment, as well as during follow-up after discharge.