Background Parental cancer as well as economic hardship in the family during childhood can affect the child negatively. Our aim was to examine the association between the joint exposure to parental cancer and income loss in childhood and the child’s socioeconomic position in early adulthood.

Methods We conducted a register-based prospective cohort study of children born in Denmark between 1978 and 1986 and in Norway between 1979 and 1987. The children were followed from 1 January 1994 (in Denmark) or 1995 (in Norway). Educational level and personal income were measured at age 30 years. Children who experienced parental cancer between the years they turned 8 and 16 years were identified, and exposure to income loss was measured in the same period. Adjusted multinomial logistic regression model was used to estimate relative risk ratios for the joint exposure of parental cancer and income loss during childhood.

Results Children who experienced parental cancer and an income loss during childhood had an increased risk of low education and lower income at age 30 years. The associations were weaker for children only exposed to income loss and less clear for those only exposed to parental cancer. Further, exposure to parental cancer with a severe cancer type was associated with lower educational level.

Conclusion The child’s educational attainment and income level in early adulthood were negatively affected by exposure to income loss in childhood, and even more so if exposed to both parental cancer and income loss. The associations with educational attainment were stronger for more severe cancer types.