The uptake of formal and informal childcare arrangements has been associated with a variety of factors related to both individual and household characteristics (age, household composition, education and labour market position of both partners,…) which affect the demand for (in)formal arrangements, as well as supply-side characteristics of both formal arrangements (cost, availability, and quality of local childcare arrangements) and informal arrangements (potential for informal care through presence of – predominantly maternal – kin, health status of potential caregivers as well as educational level and labour market position of potential caregivers). Although adequately controlling for population heterogeneity and selectivity in the uptake of formal childcare have been identified as major concerns when assessing the effect of family policies on fertility, the existing empirical literature on uptake of (in)formal childcare arrangements has typically not been able to simultaneously control for both demand-side characteristics and supply-side characteristics of formal and informal childcare at the neighbourhood level. Using linked Belgian census data from the 1991 and 2001 censuses in tandem with longitudinal microdata from the national register spanning the period 2000-2006, this papers follows young adults for a 15-year period as they move from out of the parental household and set up independent households to model uptake of (in)formal childcare arrangements in 2001 and its effects on parity progression in 2001-2006 controlling for individual and household-level labour market opportunities, proximity and characteristics of close kin as well as time varying contextual data on availability and characteristics of formal childcare arrangements at the municipality level.