Over the past two decades, immunohistochemical techniques have improved to such a degree that it is now a common adjuvant test to the traditional hematoxylin and eosin-stained histologic sections. It is used in most realms of surgical pathology and can often aid in final diagnosis and, in some cases, prognosis. However, immunohistochemistry (IHC) is not always helpful and many pitfalls to its use exist. Understanding the basics of IHC, its utility and difficulties will aid clinicians in better understanding how diagnoses are rendered. This study reviews the general principles of IHC and demonstrates its utility with several commonly encountered problematic areas in gynecological pathology.