The work of an intensive care nurse involves the direct care of patients with life-threatening conditions. In this situation, the prevention of burdens associated with this work becomes important, but it must be preceded by their diagnosis. This diagnosis is possible using standardized tools for the subjective assessment of a psychological burden and an occupational burnout. Therefore, the aim of our research was to determine whether nurses working in the same specialties in different countries are exposed to the same burdens. The study involved 312 nurses, divided into three groups depending on their country of origin and in which they worked. Two equal groups of nurses each contained 106 people from Slovakia and the Czech Republic, while the third group was comprised of 100 people from Poland. The age of the groups studied, taken together was (M = 35.53 ± 8.86 min. 22 years max. 60 years). Various results were observed as regards psychological burden and occupational burnout in the groups studied. The strongest differences related to overload, non-specific reaction to stress, feelings of personal achievement and depersonalization, which depended on age and length of service in each workplace. Assessment of the mental load can be used to improve the organization of Nurses’ work creating safe working conditions in studied countries, taking into consideration the mobility of the workforce in the European Union.