This chapter provides an overview of the major study designs for the injury-related research project, and highlights factors that guide the investigator to an appropriate design choice. It illustrates the application of several commonly used study designs to injury research through examples. The descriptive study design is a narrative account of a specific clinical injury case. Descriptive epidemiologic studies can be a rich source of hypotheses that can be followed up in analytic studies. An analytic study focuses on one or more hypotheses to be tested. Among analytic study designs, a key distinction is between intervention studies and observational studies. An important methodological issue in all observational studies is confounding. A variety of other analytic study designs are available for injury research. Most were developed for specialized research purposes and hence are less commonly used. Finally, the chapter discusses two other analytic study designs, namely case-crossover design and regression-discontinuity design.