The current study examined a new measure of squalor associated with hoarding, the Home Environment Index (HEI). Participants (N = 793) were recruited from a large database of individuals who sought information about hoarding following national media appearances and consented to an internet study. Participants completed measures of hoarding and related psychopathology, including the HEI. The HEI showed good internal consistency and construct validity and reflected a single factor of home squalor (15 items). The HEI correlated positively with measures of hoarding and mood psychopathology. Recommendations for future modifications and further study are provided.