Previous research has demonstrated that older adults are not as accurate as younger adults at perceiving negative emotions in facial expressions. These studies rely on emotion recognition tasks that involve choosing between many alternatives, creating the possibility that age differences emerge for cognitive rather than perceptual reasons. In the present study, an emotion discrimination task was used to investigate younger and older adults’ ability to visually discriminate between negative emotional facial expressions (anger, sadness, fear, and disgust) at low (40%) and high (80%) expressive intensity. Participants completed trials blocked by pairs of emotions. Discrimination ability was quantified from the participants’ responses using signal detection measures. In general, the results indicated that older adults had more difficulty discriminating between low intensity expressions of negative emotions than did younger adults. However, younger and older adults did not differ when discriminating between anger and sadness. These findings demonstrate that age differences in visual emotion discrimination emerge when signal detection measures are used but that these differences are not uniform and occur only in specific contexts.