Mulberries are healthier fruits due to their high antioxidant activities. In the present study, chemical characterization of Morus alba var. nigra fruits was investigated. The fruit chemical characters showed significant differences among the studied genotypes (P < 0.01). Total phenolics ranged from 134.73 to 922.64 mg/100 g fresh weight (FW), while anthocyanin content ranged from 25.67 to 569.69 mg/100 g FW. Furthermore, antioxidant capacity estimated by reducing power (RP) method ranged from 157.84 to 1670.00 mg/100 g FW and it varied from 109.05 to 1524.84 mg/100 g FW by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method, while it ranged from 0.59 to 12.49 mmol/100 g FW by ferric reducing antioxidant power (FRAP) method. Antioxidant capacity was found to be associated with total phenolics and anthocyanin and thus they should be considered together in breeding programs. Cluster analysis showed two distinct clusters among all the studied genotypes. Population analysis separated the studied populations into four groups. The results showed that fruits in the majority of genotypes were chemically rich and may be used in a balanced diet. Higher phenolic contents with antioxidant activity further increase their chemical potentials. The present findings are useful to understand the variability and to attempt for selecting the promising mulberries.