The effects of microRNAs on PTEN levels are characteristic for many types of cancer. However, the picture of the correlation between the expression levels of PTEN and its targeting microRNAs in endometrial cancer is not fully presented. Our study investigated and analysed the expression levels of PTEN and PTEN-targeting miR-21, miR-181a, miR-214, miR-301a, and miR-1908 in total of 78 samples, out of which 26 samples were from normal endometrium, whereas the 52 samples were from endometrial cancer samples. Our results demonstrated a high variability of individual endometrial cancer samples in the levels of PTEN. The level of miR-181a showed significant increment in endometrial cancer tissues in comparison with normal endometrium. We did not observe any statistically significant correlation between levels of microRNAs and PTEN in a heterogeneous cohort of patients. At the same time, in samples collected from endometrial cancer patients, it was found out that the relationship between PTEN expression and body mass index had significant positive correlation. Moreover, our data demonstrated that the expression of PTEN was significantly decreased, whereas expression of miR-181a was significantly over-expressed in non-obese compared to obese endometrial cancer patients. Additionally, we observed the relationship between PTEN levels and miR-181a related to the cancerous tissues for non-obese patients was established to be negatively correlated. Our findings suggest that decrease of PTEN via increase of miR-181a may be important contributor to endometrial cancer in non-obese patients.