The main aim of the study was to determine the neem and croton macrostachyus oil from Neem leave and Croton seeds, and to identify the active ingredient from the oil. For extraction of the oil, studied the effect of particle size, solvent and extraction time. A general factorial design was applied to investigate the effect of process variables on oil yield. The maximum Neem leaves oil yield 30.54% was obtained for particle size range of 0.5 mm - 1 mm at extraction time of 4 hours and with solvent ratio 40% hexane-60% ethanol. The minimum Neem leaves oil yield of 15 % was obtained for particle size range 1.18 mm – 1.4 mm at extraction time of 2 hours and with solvent ratio 60% hexane-40% ethanol. The maximum Croton seed oil yield 15 % was obtained for particle size range of 0.5 mm - 1 mm at extraction time of 4 hours and with solvent type hexane. the minimum Croton seeds oil yield of 7.5 % was obtained for particle size range 1.18 mm – 1.4 mm at extraction time of 2 hours and with solvent type ethanol. ANOVA analysis was showed significant effect of particle size, solvent ratio and extraction time on oil yield (P-value < 0.05). The physicochemical properties of the oil extracted under optimum condition were determined. The chemical compound of the Neem and Croton oil was determined by GcMs, Neem leave and Croton had 31 and 35 compounds respectively. The Neem leave oil contain several active ingredients such as delta-cadinene, eucalyptol, alpha-Terpinyl acetate and terpineol and The Croton macrostachyus oil contain several active ingredients to kill and repel insects were Epiglobulol, Copaene, (+)-δ-Cadinene, α-Cubebene and β Guaiene. The neem and croton oil were tested on mosquitoes and cockroaches.