Introduction. Staff's interaction and business communication play an important role both in the professional growth of each employee and in the work of the entire organization. Since the financial department interacts with almost all departments of the organization, the financial department staff's communication within the department and with other departments affects the work of the organization as a whole. Aim. To explore the features of the financial department staff's interaction and business communication as well as to select the instruments to conduct an empirical study of the financial department staff's interaction and business communication. Methods: theoretical analysis of the problem, analysis of empirical research methods and instruments. Results. The article substantiates the study of the financial department staff's interaction and business communication. The authors analyze the concepts of interaction and business communication, discuss the features of the financial department staff's interaction and business communication, the work of the financial department, the financial department staff's competencies and behavior, the financial department staff's business etiquette and ethics as well as analyze the methods and instruments for studying staff's interaction and business communication. Conclusions. Financial department staff should have good communication skills, because the atmosphere of friendliness, staff's care for the co-workers' needs and readiness to carry out work tasks improve work performance of not only the financial department, but also the organization as a whole. The proposed set of instruments will make it possible to determine the features of the financial department staff's communication, to find out the relationship between staff's interaction and the organization's management style, to diagnose the social and psychological climate in the department, as well as to analyze the personality traits that worsen staff's interaction and communication.