The study examines the relationship between sensory functioning (visual and auditory acuity) and intelligence in a heterogeneous sample of old and very old individuals (N = 156, M age = 84.9 years, age range = 70–103). Intelligence was assessed using 14 tests measuring five cognitive abilities: speed, reasoning, memory, knowledge, and fluency. The results show that visual and auditory acuity account for 49.2% of the total variance and 93.1% of the age-related reliable variance in intelligence. The data support structural models where age differences in intelligence are fully mediated by differences in vision and hearing. The findings suggest that sensory functioning is a strong predictor of individual differences in intellectual functioning in old age. The study discusses possible explanations, including the common cause hypothesis, which posits that visual and sensory acuity may be indicators of the physiological integrity of the aging brain.The study examines the relationship between sensory functioning (visual and auditory acuity) and intelligence in a heterogeneous sample of old and very old individuals (N = 156, M age = 84.9 years, age range = 70–103). Intelligence was assessed using 14 tests measuring five cognitive abilities: speed, reasoning, memory, knowledge, and fluency. The results show that visual and auditory acuity account for 49.2% of the total variance and 93.1% of the age-related reliable variance in intelligence. The data support structural models where age differences in intelligence are fully mediated by differences in vision and hearing. The findings suggest that sensory functioning is a strong predictor of individual differences in intellectual functioning in old age. The study discusses possible explanations, including the common cause hypothesis, which posits that visual and sensory acuity may be indicators of the physiological integrity of the aging brain.