The role of the parallel expression of the KAI1 protein and metalloproteinases (MMP-2 and MMP-9) in respect to the status of steroid receptors in endometrial cancer is still incompletely understood. The aim of this study was to evaluate the expression of and correlation between KAI1 on one hand and MMP-2 and MMP-9 on the other hand in terms of the status of the estrogen (ER) and progesterone receptors (PR) in 100 patients with endometrial cancer. The expressions of KAI1, MMP-2, MMP-9, ER and PR were assessed immunohistochemically on paraffin-embedded tissues. No correlations were found between these biomarkers and the clinical and pathological parameters of the endometrial cancer. However, in KAI1-positive cases, the expression was limited to a small area of tumor tissue in FIGO stages III–IV. A tendency towards the high expression of MMP-9 and MMP-2 was observed in the advanced stages of endometrial cancer (FIGO IIIA–IV). Positive correlations between the presence of KAI1 and PR and between the presence of MMP-9 and PR were found in endometrial cancer. A positive correlation was also observed between KAI1 and MMP-2 expression, and a borderline one between KAI1 and MMP-9 expression in endometrial cancer. KAI1+/PR+ and KAI1+/ER– immunophenotypes were observed more frequently in FIGO low stages and with well-differentiated tumor grade. However, the KAI1–/ER+ and KAI1–/PR+ immunophenotypes were mainly observed in advanced stages of endometrial cancer. KAI1+/MMP-2+ and KAI1+/MMP-9+ immunophenotypes were observed in FIGO Istage and with well-differentiated tumors. KAI1–/MMP-2+ and KAI1–/MMP-9+ phenotypes were more often observed in FIGO stage II. Our study showed that KAI1 protein, as well as steroid receptors, might modulate MMP-2 and MMP-9 expression in endometrial cancer. Our study revealed that the overlapping expression of the biomarkers investigated here suggests that cooperation between these molecules exists, even at the early stages of endometrial cancer growth, and may determine the speed of tumor cell dissemination and might characterize the biological behavior of endometrial cancer.