Description: The aim of the study was to establish the anovulatory estrus incidence in different breeds and reproductive ages of dairy cattle in Croatia, and to assess the effectiveness of hormone therapy as a treatment option. A total of 820 cows of different breeds and ages were involved in the study over two years. Anovulatory estrus was recorded in 25.61 percentage of the observed cows and heifers. The highest anovulatory estrus ratio was recorded in heifers and the lowest in cows after the 6th pregnancy (P<0.05). Regarding the breed, the highest anovulatory estrus ratio was diagnosed in crossbreeds and the lowest in the Simmental breed (P<0.05). The highest anovulatory estrus incidence was recorded during the summer months (III quartile of the year) (P<0.05). Heredity of anovulatory estrus was found to be statistically significant. Therapy success was measured by the number of days from the day of anovulatory estrus diagnosis confirmation until the day of the fifi rst artificial insemination with confifi rmed ovulation. The best results were achieved in the group T animals who were treated twice with a 20 day interval with Gonadotropin Releasing Hormone analogues (P<0.05). Vitamin (A, D, E) and mineral (Selenium) supplements in the group A cows also improved therapy results if compared to the control (untreated) group C (P<0.05), although this was less significant when compared to group T (P<0.05). We conclude that anovulatory estrus is a hereditary condition and related to a lack of Gonadotropin Releasing Hormone, as well as a lack of vitamins and minerals