Based on the literature data, the authors have investigated a number of biomarkers and determined their relationship to the development of preeclampsia in women with pre-gestational diabetes mellitus in the first trimester of pregnancy. Due to the fact that there are similar mechanisms for these conditions, the early diagnosis of preeclampsia is significantly difficult in this patient category. The authors have assessed maternal risk factors and biophysical and biochemical markers and showed their role in the prediction of preeclampsia. It has been established that in the presence of diabetes mellitus, the study of certain hormones and the markers of the inflammatory response, oxidative stress, and lipid metabolism, and adipokines may be of potential value for the prediction of preeclampsia. However, pregnancy-associated proteins and angiogenic and antiangiogenic factors, which are strong predictors of preeclampsia in women without diabetes mellitus, are shown to be a valid diagnostic tool in diabetes mellitus. Despite conflicting data, insufficient experience, and the extent of examinations, it is impossible to draw an unambiguous conclusion about the role of biomarkers in the assessment of preeclampsia in the first trimester of pregnancy complicated by diabetes mellitus. Conclusion. Thus, the active introduction of biomarkers into practice requires further and more detailed study of this area and optimization of research design.