Forty-eight lamb carcasses were divided into four groups (n=12) according to slaughter weight (24 and 29kg) and sex (male and female). Colour, pH, moisture, and intramuscular fat were not affected (p>0.05) by slaughter weight or sex. With respect to fatty acid composition, slaughter weight had significant effects on C12:0 (p<0.01), C14:0, C16:0, and C18:1 n-9 (p<0.05) in Longissimus lumborum (LL) muscle. The percentage of C12:0 and C14:0 decreased as slaughter weight increased, while C16:0 increased. In Semimembranosus (SM) m., only C18:3 n-3 and C20:2 n-6 were affected (p<0.001) by slaughter weight. Total PUFA in LL m. was greater (p<0.01) in females than in males. Although in general, sensorial quality was not significantly affected by slaughter weight or sex, meat from lighter lambs (24kg) had greater general acceptability than meat from heavier lambs (29kg).