A total number of 200 Lohman Selected Leghorn (LSL) laying hens 25 weeks of age were used to study the effect of using different levels of cassava root meal (CRM) on laying hen performance, egg quality, nutrients digestibility and economical efficiency. In this study, 0, 25 or 50% of CRM were used in isocaloric (2850 ME kcal / kg) and isonitrogenous (17 %) diets. Each level of CRM (25 or 50%) was supplemented with 0.0 or 0.20% of sodium thiosulfate (STS) as an attempt to improve the utilization of CRM in laying hen diets. Hens were kept in cages of wire floored batteries under similar conditions of management for 12 weeks experimental period. Water and feed (in mash form) were offered ad-libitum during the experimental period with 16 hours light/day regimen. The overall results showed that laying hen performance and nutrient digestibility values were decreased gradually with increasing dietary CRM level. While, adding sodium thiosulfate to dietary CRM improved the average values of both laying hen performance and nutrients digestibility comparing to those fed dietary CRM without supplementation. Data showed that there were no significant differences in the average values of egg quality (as shape index, shell thickness, Hugh units, egg total lipids and egg cholesterol) due to dietary CRM levels. However, adding 0.20% of sodium thiosulfate to dietary CRM improved the average values of economical efficiency. In conclusion, CRM could be used in laying hen diets up to 50% with addition of 0.2% sodium thiosulfate to improve laying hen performance and economical efficiency.