Purpose: To determine whether foam density affects modified Romberg balance test performance. Materials and Methods: Controls and patients with vestibular disorders performed Romberg tests on medium and medium firm foam, with their eyes closed and the head still and moving in yaw and pitch. The trial duration and number of head movements were measured. Results: Subjects aged > 60 years performed longer and with more head movements on medium firm foam than on medium foam. Older controls did not differ between medium firm and medium foam. Older patients had higher scores on head-still and head-yaw trials on medium firm foam versus medium foam but pitch trials did not differ. Females, controls, and patients had longer trial durations and more head movements on medium firm foam than on medium density foam; male controls did not differ by foam density. Male patients differed in Many clinicians use unstable foam to test standing balance. Although norms were developed using a particular type of continuously compliant medium density foam, clinicians often use other types of foam. We tested healthy adults and adults with vestibular (inner ear) disorders on the type of medium density foam used to develop the norms and on medium firm foam, which is less compliant. When the dependent measure was trial duration (s), scores were different on the 2 types of foam. Therefore, if balance scores are going to be compared to published norms, then balance tests should be given on the same type of foam with which the norms were developed.