Aim of the study: Since the establishment and maintenance of pregnancy are complex processes run by many hormones and transcriptional factors, any irregularity between proteins included in pregnancy can lead to unsuccessful conception or spontaneous miscarriage. According to researches, 75 % of failed pregnancies are caused by improper implantation. Implantation is regulated by progesterone (P) and estrogen (E), which act through their nuclear receptors (NR). The activity of progesterone receptor (PR) is modulated with NCOA-2. Activation of PR leads to transcription of Hand2. Proteins NCOA-2 and Hand2 also play a critical role in decidualization. The aim of this research was to analyze relationship between PR, NCOA-2 and Hand2 during early pregnancy. Material and methods: In this research, pregnant BALB/c mice were used. Mice were sacrificed 2, 4, 6 and 7 days after the apperance of vaginal plug. The expression of PR, NCOA-2 and Hand2 were determined by immunofluorescence of uterine tissues obtained from pregnant mice. Results: During early pregnancy, the expression of NCOA-2 and Hand2 is changing in temporal manner. There is an indication that expression of these molecules is highest at the implantation site. Colocalization of PR, NCOA-2 and Hand2 was noticed in stromal cells. Coregulator NCOA-2 is located in luminal epithelial (LE) and glandular epithelial (GE) cells. Decidual cells are NCOA-2 and Hand2 positive. Conclusion: Highly regulated mechanisms which include PR, NCOA-2 and Hand2 are essential in embryo implantation in mice. Mentioned molecules are also crucial in decidualization. Colocalization between PR, NCOA-2 and Hand2 suggests that NCOA-2 is coregulator of transcriptional activity of PR which controls the expression of Hand2 in stromal cells.