Post-infectional biochemical changes due to Xanthomonas campestris pv. mori (Xcm) infection in five elite mulberry varieties viz., $S_1$, $S_{1635}$, $V_1$, RF $S_{175}$ and JRH was studied under inoculated condition. It was revealed that total soluble sugar and protein content was significantly declined in all the varieties due to X. campestris infection. Total phenol content was at par prior to inoculation in all varieties, but it was significantly increased in $S_1$, RF $S_{175}$, $S_{1635}$ and JRH 7 days after inoculation. The correlation coefficient (r) between total soluble sugar and total phenol content was found positive (r = 0.825) and statistically significant. Similarly, correlation coefficient (r) between total soluble protein and phenol content was found positive (r = 0.897) and statistically significant. The present study indicates that X. campestris infected leaves are nutritionally inferior in quality and the duration of phenol production in a mulberry variety play decisive role on disease resistance.nce.