Case-control studies (CSS) are observational analytic studies done often in instances of rare cases or outcomes. In a case-control study, clearly defined cases and controls arising from the same population is compared for well-measured exposures. The ease of conduct of the study in terms of resources makes CSS popular. However, since the direction of the study is retrospective, selection and measurement biases are potential threats to the validity of conclusions from CSS. Moreover, CSS gives not give a direct estimate of the risk. Another issue with the CSS study is confounding. How these validity issues could be addressed are also discussed.