Analyzing examinees' responses using cognitive diagnostic models (CDMs) have the advantages of providing richer diagnostic information. To ensure the validity of the results from these models, differential item functioning (DIF) in CDMs needs to be investigated. In this dissertation, the model-based DIF detection method, Wald-CDM procedure is proposed to examine DIF in the context of CDMs. This study explores the effectiveness of the Wald-CDM procedure in detecting both uniform and non-uniform DIF in the G-DINA model through a simulation study. Furthermore, a subset of the TIMSS 2007 fourth grade mathematics assessment data was used to illustrate the use of the Wald-CDM procedure. Finally, the strengths and limitations of the proposed method, and suggestions for future studies are discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]