In recent years there have been a plethora of publications regarding the value of immunohistochemical studies in diagnosis in gynecological pathology. In many instances, papers are published initially that suggest that a certain antibody or panel of antibodies is of value in the diagnosis of a particular neoplasm and in the distinction of this from mimics. However, this is usually quickly followed by other studies that somewhat contradict these findings. The aim of this review is to present a critical appraisal of the value of immunohistochemical studies in the diagnosis of uterine neoplasms with emphasis on the recent literature. It is stressed that immunohistochemistry is necessary in relatively few cases and a knowledge of the potential immunoreactivity of utilized antibodies is required. With regard to endometrial carcinoma, topics discussed in this review include antibodies of value in the distinction between type 1 and type 2 carcinoma, in the characterization of focal serous proliferations in endometrial polyps and non-polypoid endometrium, in the sometimes problematic distinction between an endometrial and an endocervical adenocarcinoma, and in the distinction between a uterine and ovarian serous carcinoma. The value of CD10 as a proposed marker of mesonephric adenocarcinoma is also discussed. With regard to uterine mesenchymal neoplasms, a critical appraisal of the value of relatively new antibodies, including CD10 and h-caldesmon, in distinguishing between a smooth muscle and an endometrial stromal neoplasm is discussed as is the immunophenotype of two rare uterine mesenchymal neoplasms, uterine tumor resembling ovarian sex cord tumor (UTROSCT) and perivascular epithelioid cell tumor (PEComa).