OBJECTIVES: Living in low socioeconomic conditions during childhood is associated with poor health outcomes in later life. Whether this link also applies to cancer is unclear. We examined whether childhood socioeconomic conditions (CSCs) are associated with cancer risk in later life and whether this effect remained after adjusting for adulthood socioeconomic conditions (ASCs). METHODS: Data for 26,431 individuals ≥ 50 years old included in SHARE were analysed. CSCs were constructed by using indicators of living conditions at age 10. ASC indicators were education, main occupation, and household income. Gender-stratified associations of CSCs with cancer onset (overall and by site) were assessed by Cox regression. RESULTS: In total, 2852 individuals were diagnosed with cancer. For both men and women, risk of overall cancer was increased for advantaged CSCs and remained so after adjusting for ASCs (hazard ratio = 1.36, 95% CI 1.10, 1.63, and 1.70, 95% CI 1.41, 2.07). CONCLUSIONS: Advantaged CSCs are associated with an increased risk of overall cancer at older age, but results vary by cancer sites and sex. Participation in cancer screening or exposure to risk factors may differ by social conditions.