BACKGROUND: A decade ago it was reported that childhood cancer incidence was higher in boys than girls in many countries, particularly those with low gross domestic product (GDP) and high infant mortality rate. Research suggests that socio-economic and cultural factors are likely to be responsible. This study aimed to investigate the association between cancer registration rate sex ratios and economic, social and healthcare-related factors using recent data (1998-2002). METHODS: For 62 countries, childhood (0-15 years) cancer registration rate sex ratios were calculated from Cancer Incidence in Five Continents Vol IX, and economic, social and healthcare indicator data were collated. RESULTS: Increased age standardised cancer registration rate sex ratio (M:F) was significantly associated with decreasing life expectancy (P=0.05), physician density (P=0.05), per capita health expenditure (P=0.05), GDP (P=0.01), education sex ratios (primary school enrolment sex ratio (P<0.01); secondary school enrolment sex ratio (P<0.01); adult literacy sex ratio (P<0.01)) and increasing proportion living on less than Int$1 per day (P=0.03). CONCLUSION: The previously described cancer registration sex disparity remains, particularly, in countries with poor health system indicators and low female education rates. We suggest that girls with cancer continue to go undiagnosed and that incidence data, particularly in low- and middle-income countries, should continue to be interpreted with caution.