'Arnoia' peppers (Capsicum annuum L. var. annuum cv. Arnoia) are cultivated in areas surrounding the Arnoia River, in Galicia (northwest Spain). Some physical and chemical changes associated with maturation and storage conditions have been reported. Changes in gross composition, the main physico-chemical parameters and mineral composition were evaluated in peppers collected directly from plants and at two different states of maturity (green and red fruits), and in commercially available peppers (green fruits). The total soluble solid content and titratable acidity increased significantly during ripening. The fat, ash and protein contents were generally significantly higher in the red pepper than in the green peppers. The total ascorbic acid in red peppers was 27% higher than that of green peppers. The vitamin C content of commercially available green peppers was up to 39% lower than in the freshly picked peppers. Potassium was the most abundant mineral in green and red peppers. Green peppers purchased in the supermarket contained higher amounts of calcium and sodium than the freshly picked peppers. The levels of zinc, manganese and copper were similar in all of the different samples.