Special status of PhD students
Full-time PhD students are considered to be students, not employees; hence a university is not in the position of their employer in relation to their social and health insurance. Full-time PhD students at Slovak universities or external education institution (institutes of the Slovak Academy of Sciences) receive a scholarship provided from the state budget. PhD scholarships provided by the state are exempt from the income tax.
Students with a permanent residence in an EU Member State are entitled to receive a PhD scholarship from the state budget, unless they have already been awarded a PhD degree, in the amount stipulated in the Act on Certain Public Servants Remuneration.
If you want to be employed during your studies in Slovakia, look at the part Work carried out occasionally.