In Tunisia, the protection of groundwater resources, widely attacked by anthropic activities, against its contamination by nitrates has prompted the state to implement a national network for monitoring groundwater quality. The present work aims the characterization of the nitric quality of five aquifers in Kasserine region (Central West of Tunisia) and the identification of potential sources of water pollution. The study involved 22 wells water surface followed during 17 years (1996-2013). The temporal variation of nitrate showed a significant contamination with a concentration greatly exceeding the recommended norm during the period 1999-2003. The latter coincides with the phase of agricultural intensification related to the non-reasoned application of fertilizer coupled with the bad irrigation management. Nevertheless, between 2004 and 2013, the contamination tends to decrease and nitrates concentrations have stabilized around the potability threshold. The results also showed that nitrates levels are related to the soil type, irrigation techniques adopted by farmers and nitrogen supply. Indeed, excessive nitrogen inputs with a coarse texture and a gravity irrigation technique tend to increase the concentration of well water by nitrates. However, correlation between nitrates, piezometry and climatic factors, particularly, the rainfall could not be highlighted in the study area.