There is a growing interest in understanding the effect that online information-seeking has on patients’ experiences, empowerment and interactions with healthcare providers. This mixed-methods study combines surveys and in-depth interviews with 41 parents of paediatric cancer patients in the USA to examine how parents think about, evaluate, access and use the internet to seek information related to their child's cancer. We find that, during the acute crisis of a child being diagnosed with cancer, parents preferred to receive information related to their child's diagnosis, prognosis and treatment options from a trusted healthcare provider rather than through the internet. We find that access to medically related cancer information through the internet was deemed to be untrustworthy and frightening. Parents’ reasons for avoiding online information-seeking included fear of what they might find out, uncertainty about the accuracy of information online, being overloaded by the volume of information online and having been told not to go online by oncologists. Some parents also had logistical barriers to accessing the internet. While most parents did not turn to the internet as a source of health-related information, many did use it to connect with sources of social support throughout their child's illness.