Nutrition knowledge enables informed dietary choices. This paper reports on the nutrition knowledge of older adults residing in sheltered housing accommodation in socially deprived areas of north-east England. As part of a cluster randomized dietary intervention trial, a validated questionnaire measured the knowledge of current dietary recommendations, nutrient sources, ability to select healthy meal options and knowledge of associations between diet and diseases of older adults aged 60 years and over residing in sheltered accommodation. Completed questionnaires were obtained from 177 (59%) subjects (147 female, 30 male), of whom 76% were overweight/obese and 2% underweight. The mean (SD) age was 76.4 (8.0) years. Of a possible score of 47, the mean score was 23.2, indicating that approximately 50% of questions were answered incorrectly. Knowledge of associations between diet and diseases was particularly poor; 90% of subjects being unaware of the benefits of high fruit and vegetable consumption. Respondents in the highest 10% of the nutrition knowledge score had a significantly higher intake of fruit and vegetables compared with those in the lowest 10%. A high proportion of older adults had little basic nutrition knowledge; this presents a barrier to healthier eating that should be addressed.