Comfort in interacting with people with intellectual disabilities is an important quality for effective professionals. A measure of this variable, the Interaction with Disabled Persons (IDP) Scale (Gething, 1991) was completed by 468 tertiary students, 135 of whom were 1st-, 2nd-, or 3rd-year students of the Bachelor of Applied Science (Intellectual Disability). Items from the scale were presented intact, as well as being dispersed within a broader attitude questionnaire. Retest data were collected (n = 81), and a sub-sample (n = 29) responded to the Marlowe-Crowne Social Desirability Scale (Crowne & Marlowe, 1960). The IDP Scale discriminated between student groups, and this effect was robust when age, gender, and contact with people with intellectual disabilities were treated as covariates. Score distributions were adequate, and there was no evidence of the influence of social desirability. Reliability was optimised by excluding some items and introducing others. The modified measure was relatively cohesive, stable, and balanced in terms of positively and negatively worded items. Factor analysis identified a six-factor structure.