Many standardized measures of cognition include items that must be seen or heard. Nevertheless, it is not uncommon to overlook the possible effects of sensory impairment(s) on test scores. In the current study, we investigated whether sensory impairments could affect performance on a widely used screening tool, the Montreal Cognitive Assessment (MoCA). Three hundred and one older adults (mean age = 71 years) completed the MoCA and also hearing and vision tests. Half of the participants had normal hearing and vision, 38% impaired hearing, 5% impaired vision, and 7% had dual-sensory impairment. More participants with normal sensory acuity passed the MoCA compared to those with sensory loss, even after modifying scores to adjust for sensory factors. The results suggest that cognitive abilities may be underestimated if sensory problems are not considered and that people with sensory loss are at greater risk of cognitive decline.