The aquifer of Metline is located in the north of Tunisia and represents an alluvial aquifer facing the Mediterranean Sea. DRASTIC model was applied with a GIS system to evaluate the vulnerability of the aquifer to pollution. Data related to the study area and corresponding to seven critical factors of the model (depth of water, net recharge, aquifer media, soil media, topography, impact of the vadose zone, and hydraulic conductivity) was attributed to the factors according to their importance in the vulnerability model. By summing the product of weights and indexes of the critical factors, the obtained hydrogeological vulnerability map showed five classes of potential pollution of the study aquifer.