Abstarct: Abstract The present study aims to investigate the environmental geochemistry of potentially toxic elements (PTEs) in urban and agricultural soils of Islamshahr, Tehran province. For this purpose, 21 urban and agricultural surface soil samples were collected. The total concentrations of PTEs were measured by ICP-OES after strong hot acid digestion of the soil samples. The obtained data were analyzed through the calculation of geochemical indices (i.e., enrichment factor, geoaccumulation index, single factor pollution index, potential ecological risk index, combined pollution index, pollution load index, and integrated mextal index), and statistical methods (correlation coefficient and cluster analyses). baxsed on the results, the average total concentration of Al, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sc, Ti, Zn, and Zr are 61647, 0.22, 12.4, 58.4, 29.9, 31627, 895, 1.2, 38.1, 35.9, 10.4, 3052, 129, and 284 mg/kg, respectively. The values of the enrichment factor confirm that while the studied soils are moderately enriched with Th and Mn, there is low enrichment of the samples with other studied elements. The statistical analyses of the obtained data show that while Co and Mn are mainly from natural sources, Cr, Fe, Zn, Cu, As, Cd, and Pb originate from anthropogenic activities (e.g., industrial activities, traffic, urban and industrial waste disposal centers). Human health risk assessment shows the non-carcinogenic risk of Pb through ingestion for children in some sampling stations. The carcinogenic risk of Cd in the soils of the study area is within the acceptable range (1×10-6 – 1×10-4) for both adults and children, while ingestion of Cr and Ni may pose a risk of cancer for children.