Background: The successful incorporation of fish oil into foods may provide a means of increasing intakes of n-3 polyunsaturated fatty acids (n-3 PUFA). The aim of the present study was to evaluate the bioavailability of n-3 PUFA in microencapsulated fish oil compared with a fish oil capsule. Methods: Twenty-eight healthy volunteers were recruited to take part in this randomized controlled trial. Volunteers were supplemented with 0.9 g n-3 PUFA daily for 4 weeks, delivered either as microencapsulated fish oil in a milkshake or as a fish oil capsule. Plasma fatty acid composition and plasma total cholesterol levels were measured at baseline and after supplementation. in addition, volunteers completed a questionnaire on fish consumption, use of supplements and exercise. Results: Responses to the questionnaire indicated that the males who took part in this study took more physical exercise, consumed less fish and were less likely than the females to take supplements. Plasma n-3 PUFA concentrations were raised significantly and by a similar level by both fish oil supplements. Furthermore, no significant difference was observed in plasma n-3 PUFA concentrations following supplementation with either form of fish oil. Plasma total cholesterol levels were not significantly altered by n-3 PUFA supplementation in either group. Conclusion: The results of this study indicated that there was no difference in the bioavailability of n-3 PUFA given as microencapsulated fish oil compared with n-3 PUFA delivered as a fish oil capsule. Fortification of foodstuffs with microencapsulated fish oil therefore offers the potential to increase intakes of n-3 PUFA in line with current recommendations.