The objective of this study was to evaluate and compare, for the first time, white and black mulberry species in terms of their main physicochemical characteristics in eight Spanish clones. The results showed significantly different characteristics between the black and white mulberry species. Fruit weight of mulberry species ranged from 2.10 to 4.15 g, and fruit juice yield, from 41% to 62%. Fructose (~61%) and glucose (~39%) were the predominant sugars in all mulberries. The MN1 clone displayed the highest total acidity (>2.6 g L−1), and malic acid was the most abundant organic acid (6.65 g kg−1). Cluster analysis has allowed grouping of the clones into three groups (i) MN1 and MN2; (ii) MN3 and MN4; and (iii) MA1, MA2, MA3 and MA4. Experimental results proved that Spanish mulberries have high potential for fresh consumption (attractive dark colour in Morus nigra clones, high sugars content and intense sweetness) and industrialisation (~50% juice yield, attractive juice colour, high content of crude fibre and intense sweetness). This study is also a step towards identification of this fruit as a potential healthy food, which may also be used in food industry and also have pharmaceutical interest.