Pomegranate fruit is valued for its juice-containing arils and is consumed and marketed as whole fresh fruit, extracted arils, juice, syrup (grenadine), wine, teas, seed oil, and other products. Recent consumption has rapidly increased attributable in part to reported health benefits that include efficacy against coronary heart disease, atherosclerosis, cancer, hypertension, and infectious diseases. Within commercial orchards, the size of fruits produced can be quite variable even with trees of the same genotype grown under similar cultivation practices. Although pomegranates have been cultivated since antiquity, fruit attributes, particularly those related to size, are poorly defined. In this study, compositional changes in pomegranate fruits of the Wonderful cultivar, including volume and weight, aril weight and number, pericarp weight, seed weight, and juice/pulp content, were evaluated in fruits of variable sizes. Correlations between fruit characteristics were determined, and factor analysis established fruit and aril indices. Results indicated that because fruit volume, fruit weight, and total aril weight are closely correlated, any of these characteristics can be used as an indicator of fruit size. The number of arils per fruit was highly correlated with fruit size with larger fruit containing greater numbers of arils. This is in contrast to individual average aril weight, which showed no significant relationship to fruit size. Crop production strategies aimed at increasing aril numbers may be a means for obtaining larger fruit in pomegranate.