The present study aimed to assess the content of bioactive phytochemicals (total phenols, flavonoids, tannins, saponins and alkaloids), and to determine the best extract for potent insecticidal activity in the leaves and stem bark of the medicinal plant Ziziphus spina-christi (Rhamnaceae) from south-east Algeria against the aphid Aphis fabae (Aphididae). The extraction was done using different solvents (N-hexane, DCM, MeOH, and Water). The insecticidal activity of the extracts was determined using a contact toxicity test on Aphis fabae larvae and adults. Our results show that for leaves, the highest levels of polyphenols and saponins were observed in the MeOH extract (58.27 mg GAE/g DW and 320.93 mg CE/g DW respectively), with the highest mortality in larvae and adults (89.411 and 81.538% respectively) at the 60 mg/ml concentration, and LD50 values of (17.747 and 21.819 mg/ml respectively). In addition, the MeOH extract of stem bark was the richest in polyphenols and saponins (185.96 mg GAE/g DW and 662.47mg CE/g DW respectively), resulting in higher toxicity than the MeOH extract of leaves. On the basis of these results, we believe that Z. spina-christi is an excellent source for the isolation of compounds as alternative insecticidal agents that are safer than the use of chemical pesticides.