Cost-of-illness (COI) analysis was the first economic evaluation methodology used in the health field, and it aims to identify and quantify all of the costs incurred due to a particular illness. While cost-of-illness studies attract much interest from healthcare policy makers and public health advocates, inconsistencies in study methodologies and cost inventories have made cost-of-illness estimates difficult to interpret and compare, limiting their usefulness. The purpose of this thesis was to use a scoping review approach to systematically explore cost inventories in the cost of foodborne illness literature, and to investigate the association between study methodologies, component costs, and foodborne illness-related factors to the estimated cost of non-typhoidal Salmonella spp. illness, using studies identified in the scoping review. The results indicated high variability in terms of the depth and breadth of individual and societal level component costs, along with a wide range of data sources being used in the cost of foodborne illness literature. Additionally, the number of direct component cost categories included in an estimate, particularly long-term care costs, and the inclusion of chronic sequelae costs were significantly associated with the cost of non-typhoidal Salmonella spp. illness. Therefore, these may be important factors to consider when initiating a cost of foodborne illness study and when interpreting or comparing existing cost of foodborne illness estimates. The results of this thesis can be used to address issues that are believed to be limiting cost-of-illness studies as decision making tools, and to better understand factors which may impact a cost of foodborne illness estimate. / Scoping review and linear regression analyses in the area of cost of foodborne illness / Canadian Institutes of Health Research/Public Health Agency of Canada (CIHR/PHAC) Applied Public Health Research Chair (awarded to Dr. Jan M. Sargeant)