1. An assessment of the Islanders' food consumption on Tristan da Cunha before the volcanic eruption of 1961 was made (Part 1). The mean daily intake of energy was 2030 kcal per person and the calories derived from protein, fat, carbohydrate and alcohol accounted for 21, 26, 50 and 3% respectively of the total calorie intake, the proportion of calories derived from protein being about twice that found in other types of diet. 2. The weekly food intake of thirty-seven families resident at Calshot, Hants, was measured in July 1963, 3–4 months before the Islanders left England to return to Tristan da Cunha (Part 2). The mean intake of energy was 1750 kcal per person per day and the calories derived from protein, fat and carbohydrate accounted for about 12, 41 and 47% respectively of total calorie intake, proportions similar to those found in present-day British diets. The proportion of other nutrients in relation to calories also resembled those in British diets, except for vitamin A and ascorbic acid, which were relatively low in the Tristan diet. 3. A comparison of the results for the Islanders with those for a sample of households surveyed for the National Food Survey was made. The Islanders consumed less of all nutrients, and the average energy value met only 65% of estimated requirements compared with 108% in the British sample. 4. Details of foods consumed and of the Islanders' food patterns and preferences are given. There is some evidence that the Tristanidns did not like their former staple foods, potatoes and fish, as available in England, though at the time of the survey they had not appreciably switched to the British staple, bread. 5. The relatively low food intake reported in this study conforms with that recorded in the Norwegian investigation of 1937–8 (Henriksen & Oeding, 1946) and with calculations of island food supplies before 1961 (Part 1). 6. Possible explanations for the low food intake are discussed. It is suggested that the Islanders may not be very active and that energy balance studies on individuals who have returned to Tristan da Cunha might throw some light on the results of this survey.