Abstract. Despite the rapid increase in families headed by single mothers, sufficient attention has not been paid to the living arrangements of these families. Most prior research has generally relied on Bureau of the Census definitions as household head and subfamily head to categorize single mothers' living arrangements. This two part grouping, however, obscures the actual diversity of living arrangements undertaken, including cohabitation with unrelated males. This paper moves beyond the standard two part grouping of single mothers and instead provides a detailed taxonomy of single mothers' living arrangements using data from the Current Population Survey. Among the findings, the economic status of families headed by single mothers varies tremendously by living arrangement, a fact which has been entirely overlooked in earlier research.