The genus of Chlorella is widely used in environmental research, especially in wastewater treatment. The aim of the present work is to study the growth of the microalgae Chlorella sp isolated from clean lagoon, and to investigate its capacity to treat Jbel Chakir landfill leachate. The growth rate of Chlorella sp. and its ability to remove organic carbon (Chemical Oxygen Demand: COD) and ammoniacal nitrogen (NH4+-N) were determined in a serial dilution of leachate. The results showed that the development rate of this microalgae at 10% of leachate (2.7) is similar to the one registered for the reference growth Bold's medium (2.6). When leachate rate exceeds 30%, a good growth of Chlorella sp. was observed after a pre-adaptation of 14 days. This growth is comparable to the one recorded for the Bold's medium. A removal rate of COD (60%) and NH4+-N (100%) were achieved by Chlorella sp. with a positive correlation between growth and nutrient intake constantly recorded. Chlorella sp. could resist and grow up in the raw leachate of Jbel Chakir landfill that results a decrease of mineral and organic contents.