In this article, we present the results of organ-preserving treatment applied in 24 patients of reproductive age with atypical endometrial hyperplasia or early-stage endometrial cancer. All of them would like to preserve their reproductive potential. Thirteen women with atypical endometrial hyperplasia were treated with the combination of six intramuscular injections of 3.75 mg gonadotropin-releasing hormone agonist (GnRHa)--leuproreline acetate depot every 4 weeks. After the third injection of 3.75 mg of leuproreline acetate, the levonorgestrel intrauterine hormonal system containing 52 mg levonorgestrel (Mirena®, Bayer, Germany) was inserted for at least 6 months. In 11 women with stage IA well-differentiated endometrial adenocarcinoma, hormonal therapy included nine intramuscular injections of 3.75 mg of GnRHa every 4 weeks. After the third injection of 3.75 mg of GnRHa, we also inserted a GnRH-IUS (Mirena®) for at least 12 months. This type of therapy was effective for all these patients and may be offered to be used as an alternative to surgery in women with atypical endometrial hyperplasia or early stage 1A well-differentiated endometrial cancer in women of reproductive age. Three women with endometrial cancer became pregnant and two of them delivered at term and one has an ongoing pregnancy.