Restriction of food to ewes bearing twin lambs showed a trend to decrease the level of omega 6 fatty acids in muscle phospholipids of the foetus though this was not significant statistically (P less than 0.05). 2. There was a significant increase in the fatty acid ratio, 20:3 omega 9:20:4 omega 6 in the twin lambs as compared with single lambs. 3. There were no symptoms of polyunsaturated fatty acid deficiency.