Overall composition, and fatty acid, amino acid, and nucleotide-type compound levels in wild (Haliotis gigantea) and cultured abalone (Haliotis discus hannai), were investigated. Wild abalone had a higher moisture content than did cultured abalone, but the converse was true for crude protein content. In overall composition, crude lipid level was higher in the viscera than in the meat, with the greatest level, $2.02{pm}0.15%$ (w/w), observed in the viscera of wild abalone. The major fatty acids were palmitic acid (16:0), oleic acid (18:1n-9), eicosatrienoic acid (20:3n-3, ETA), eicosapentaenoic acid (20:5n-3, EPA), and docosahexaenoic acid (22:6n-3, DHA). The omega-3 fatty acid content (EPA and DHA) was higher in wild than in cultured abalone. A total of 17 amino acids were detected in all abalone samples, most of which had high levels of aspartic acid, glutamic acid, glycine, and arginine, and low amounts of cysteine, methionine, and histidine. Glutamic acid was the most abundant of all amino acids. The content of free amino acids was related to taste score. The major free amino acids were taurine, alanine, and arginine, of which taurine was the most abundant, and was present at higher levels in wild compared to cultured abalone. The total contents of nucleotide-related compounds in wild and cultured abalone were 12.93 mg/100g and 30.75 mg/100g, respectively.