Background: Albendazole (ABZ) and albendazole sulfoxide (ABZSO) have a basic role in the treatment of hydatid cysts. However, their poor solubility and limited intestinal permeability are the main problems in their formulation. Objectives: The preparation and characterization of ABZ and ABZSO-loaded solid lipid nanoparticles (SLNs) to increase the hydatid cyst membrane permeation by loading into SLNs. Materials and Methods: First, ABZ and ABZSO-loaded SLNs were prepared by micro emulsification and high shear homogenization. Physicochemical characterization of the formulations for particle size, polydispersity index, drug entrapment efficiency (EE) and drug loading (DL), zeta potential, particle shape, drug stability, and in vitro drug release studies were evaluated. Next, the permeability of conventional and prepared formulations on hydatid cysts was evaluated by quantifying the drug concentrations in cyst fluid using high-performance liquid chromatography (HPLC). Results: The prepared formulations showed particle sizes < 180 nm, polydispersity index values around 0.08 with narrow size distributions, a high EE of (91%) for ABZ-SLN and (94%) for ABZSO-SLN, and ideal stabilities with regard to their largely negative zeta potentials. The in vitro drug release of free drugs exhibited very fast release in the initial time, but displayed a biphasic pattern for drug-loaded SLNs. Greater permeability was achieved using the SLN preparations. Conclusions: ABZ and ABZSO achieved good physicochemical characterizations, controlled release, higher permeability and efficacy by loading into SLNs, and are promising for the treatment of this disease.