Significant genotypic variability was found in total fat, fatty acid and cr-tocopherol contents and lipoxygenase (LOX) activity of kernels of Corylus avellana cultivars Barcelona, Ennis, Tonda Gentile Delle Longe (TGDL) and a wild hazelnut, Corylus cornuta. Relationships existed between shelf-lives for kernels/nuts of these cultivars and polyunsaturated fat, alpha-tocopherol and LOX activity levels. Barcelona and Ennis, previously shown to be less resistant to oxidative deterioration (shorter shelf-lives), were higher in polyunsaturated fat and LOX activity. Conversely, the antioxidant alpha-tocopherol was present in higher concentrations in the more stable TGDL than in the other cultivars. There was no apparent relationship between shelf-life and mineral or protein content.