Irrigation water can cause damage to irrigated crops and human and animal’s health. Therefore, it is important to monitor the irrigation water regularly. There is a long-term tradition of irrigation water quality (IWQ) monitoring in Slovakia. A number of monitoring stations varied during years from more than 200 to 11 in recent years. The IWQ increased over the years. Advantages of the irrigation water monitoring helps in increasing quality of agriculture production, in a reduction of a risk of bacterial, respectively, and in reducing virus infection of humans and animals.