Children of depressed parents are at increased risk of developing mood disorders but mechanisms of intrafamilial transmission are currently unclear. One rarely investigated area is the impact of depression on a parent's everyday functioning. Currently there are no validated assessments of depression-specific parental impairment. The creation of such a measure would complement depression symptom counts, providing a more comprehensive account of the parent's depression. We therefore aimed to develop a valid and reliable measure of impairment specifically associated with parental depression. In a longitudinal study of parents with recurrent unipolar depression and their offspring, we collected data from 337 parents. These participants completed the Depression Impairment Scale for Parents (DISP), a questionnaire assessing depression-associated impairment in multiple domains of functioning. Factor analysis revealed that this measure consisted of two factors - impairment in routine tasks/activities and impairment in family functioning - that together accounted for 51.04% of variance. The scale evidenced good internal consistency (Cronbach's alpha=0.82). The DISP also displayed good construct and criterion validity as evidenced by significant associations with established measures of depression severity and global impairment. These results demonstrate that the DISP is a valid and reliable measure of depression-associated impairment in parents. © 2013 Elsevier Ireland Ltd.