Fatty acid composition, marbling score and melting point data collected between 1994 and 1996 were analysed. The data were from the adipose tissue of 764 Angus, Belgian Blue, Hereford, Jersey, Limousin, South Devon and Wagyu crossbred cattle slaughtered after lot-feeding at 500 days of age. The aim was to investigate sire-breed differences and to estimate heritability and genetic and phenotypic correlations. Significant breed differences were found: Jersey crosses had the highest marbling score and Belgian Blue crosses had the lowest. Limousin crosses had the highest melting point and Jersey crosses the lowest. South Devon crosses had the highest proportion of stearate and Jersey crosses the lowest. Desaturation indices in C16 and C18 fatty acids were highest in Jersey crosses and lowest in Limousin and South Devon crosses. In contrast, there were no breed differences in the proportions of palmitate, oleate, total saturated, total mono-unsaturated fatty acids and elongation index. Heritability estimates of individual fatty acids and their summations, melting point and marbling were low to moderately low (0.05 to 0.27). Strong genetic correlations of melting point and desaturation index in C16 fatty acids (-0.93), melting point and stearate (0.62), marbling and stearate (-0.71) and marbling and desaturation index in C18 fatty acids (0.62) were observed. Phenotypic correlation were generally low. The results imply that fatty acids in the adipose tissue of lot-fed cattle have a moderately low heritability, hence genetic progress might be slow.