Thepurposeofthisstudywastodeterminetheconcentrationoflead(Pb)in Cymodoceaserrulatatissues(roots, rhizomes,andleaves)usingtheAASmethod,alsotofigureoutPb’simpactonseagrass’histologyandelementsusingthe SEM-EDXMapping method. The results showed that the higher the concentration and the length of the planting period, the higher the accumulation of heavy metals in the seagrass tissues. In this study, Pb was largely accumulated in the leaves,roots,andrhizomestissue.Moreover,theseagrasshistologyintheepidermisandendodermisunderwentshape and structure changes; it also went through damage or thickening at 15 ppm concentration, compared to control. This study strengthens the usefulness and relationship of Cymodocea serrulata seagrass as a biological indicator of metal contamination in the waters.Keywords: Cymodocea serrulata; lead; mapping; seagrass; SEM EDX