Background: Cystic echinococcosis (CE) is considered as a neglected disease that imposes noticeable medical and economic challenges worldwide. Cinnamon oil (CO) has demonstrated potent antimicrobial effects even on hydatid cysts protoscoleces. We aimed to synthesize Cinnamon oil-loaded Solid lipid nanoparticles (CO-SLNs) and to evaluate the protoscolicidal effects of this formulation. Methods: CO-SLNs were prepared using an emulsification, probe sonication technique, incorporating natural lipids (cholesterol and lecithin). SLNs were evaluated based on particle size, polydispersity index (PDI), zeta potential, electron microscopy, encapsulation efficiency (EE%) and cell compatibility (MTT assay), etc. The scolicidal activity was assessed using the eosin exclusion test (eosin 0. 1%) at concentrations of 0. 5, 1, 2, 4 and 8 mg/ml of CO and CO-SLNs for time intervals of 10, 20, 60, 120 and 180 minutes and 24 h. Results: Characterization of the CO-SLNs showed an average size of 337. 6 nm with PDI 0. 77 and zeta potential of-26 mV and EE of 83. 49% with round morphology. The MTT assay showed a higher cell viability in CO-SLNs compared to CO. A 100% mortality rate of PCs was observed for CO-SLNs at a concentration of 8 mg/ml after 120 minutes and for free CO at a concentration of 8 mg/ml after 30 minutes. Conclusion: CO-SLNs exhibited a milder scolicidal activity than free CO, which may be due to the sustained release of the oil from SLNs, resulting in a longer effective period and lower toxic effects on normal cells.