Abstarct: The environmental contamination of mining and smelting activities is of growing concern in recent decades. In this study, an assessment is made to determine the extent of contamination and to discriminate the possible origin of mextals in soils around Zanjan zinc smelting unit (NILZ), NW Iran. 28 topsoils and 9 subsoils samples were collected from the surrounding soils along transect from the smelter. Total mextal concentration in samples along with soil physicochemical properties (organic matter content, pH and clay content) were determined. In addition, geochemical speciation of mextals in some soil samples was determined by BCR sequential extraction procedure. In order to analyze the obtained results, multivariate statistical analyses (cluster and principal component methods) were used to determine the origin of mextals and their relationship with soil properties. The results revealed that physicochemical properties are relatively invariable in surrounding soils. The geochemical results also showed that the concentration of mextals in some parts of the region (especially NW and SE downwind direction) is heavily polluted by Pb, Zn, Cd & As even 20 times higher than World Mean Soils. Since the tailing heaps have been dumped in northern part of the smelter plant, nearest points to the smelter suffer from extreme heavy mextal contamination. The results generally revealed that most heavy mextals (Pb, Zn, As and Cd) concentrations decreases as distance from the smelter increases both in downwind (NW) and upwind (SE) direction, expressing the prevalent wind effect on the distribution of the investigated mextals in topsoil samples (0-10 cm in depth). On the other hand, the concentrations of mextals such as Cu, Ni and Cr show an increased trend with increasing distance from the smelter. Depthwise distribution of the heavy mextals also indicated that in a profile sampled next to the tailing heap, concentration of some heavy mextals, notably Cd and As increases suggesting the effect of surface leaching on distribution of this mextal in affected soils. Calculation of some geochemical indices also indicated that the soil is affected by emissions from the smelter. Air-born particulate with high content of mextals (emitted from stack of furnace) is probably the main route for soil contamination in NW transect. In SE transect, tailing heap (composed of soil chemical wastes) are presumed as the main source of soil contamination. The results of statistical approaches showed that the mextals Pb, Zn, Cd and As are evidently related to human activities (smelter) in the study area whereas mextals such as Cu, Cr and Ni are mainly of natural origin. Also, sequential extraction method donated that mextals Pb, Zn and Cd were bounded to liable fractions (exchangeable and carbonate bound) while Ni was associated with residual fraction.