Oleander is an evergreen shrub or small tree from 5 to 25-ft tall containing gummy sticky sap in the dogbane family apocynaceae. In this study, the alkaloid compounds of Nerium oleander (NO) have been evaluated. The chemical compositions of the leaf methanol extract of Nerium oleander were investigated using gas chromatography- mass spectroscopy. GC-MS analysis of Nerium oleander alkaloid leaf methanol extract revealed the existence of the 5-Hydrooxy methylfurfural, ?-d-allopyranoside, methyle 6-dioxy-2-o methyl, 2-Cyclopenten-1-one, 2-hydroxy-3-methyl, 9.12.15-Octadecatrienoic acid,2,3bis[trimethylsilyl]oxy] propyl ester, Octadecane, 3-ethyl-5-(2-ethylbutyl), 1-Monolinoleoylglycerol trimethylsilyl ether, 2-Cyclohexen-1-one, 4-(hydroxybutyle)-3.5.5-trimethyl and 3-Eicosene. Eight chemical alkaloids constituents have been identified from methanolic extract of the Nerium oleander.