Although there is a wealth of research on the relationship between income level and employment status and child well-being, the relationship between economic instability and health during early childhood is understudied. We examine the associations between the incidence, accumulation, and timing of intrayear employment and income instability with household and child food insecurity and child health using a nationally representative sample of households. The sample includes children age 3–5 from households in the 2008 Survey of Income and Program Participation (N = 5,056). We find that young children’s households experience high levels of both income and employment instability. Both the incidence and the accumulation of instability predict poorer child outcomes, more recent instability is more strongly associated with child outcomes, and these relations are stronger for children with less educated parents. Employment and income changes have separate, unique associations with each outcome and operate in somewhat different ways.