Modern technologies ask anew the old question about how employees can be checked during working hours so that legitimate interests of their employers are safeguarded. The answer cannot be solely technological, as the employees right to privacy, even in the workplace, is protected at the highest constitutional as well as international levels. Employers when defending their rights and interest are therefore far from free to use the potential of available technological devices in full and without limits. To strike the right balance between legitimate interests and fundamental rights is by no means easy, as the present text tries to demonstrate by summarizing and analyzing the existing Czech approach to the issue. On the one hand, Czech law on the protection of privacy of employees in the workplace, as well as the authorities applying it, are principally in line with generally accepted European standards. On the other hand, however, this basic consensus on values and their substantive and procedural legal safeguards does not mean that Czech law currently answers all questions and leads employers safely outside the restricted zone of prohibited ways of employee monitoring. The focus of the text is thus directed at those provisions of legal acts, decisions of the highest courts, opinions of supervisory authorities and arguments of commentators that influence the way in which the aforementioned rights and interest are balanced in the current Czech legal practice.