Operational risk results from inadequate procedures, systems, human error or inadequate application of appropriate methodology in banking operations. Although operational risk was seen in traditional banking, modern electronic banking emphasized its significance and crucial role in the process of realization of superior corporate performances of banks. Operational risk management involves continuous identification, measuring, monitoring and control with the purpose of minimizing waste. Basel II suggests a basic indicator approach, standardized approach and advanced measurement approach to operational risk with national regulators specifying detailed management methodology. In this regard, criteria under which the second and the third approach can be used should be clearly defined. The first part of the paper deals with operational risk determinants, sources and modalities. The second part of the paper focuses on operational risk quantification in accordance with different approaches suggested by the Basel II standard. The third part of the paper presents theoretical and methodological matrix for operational risk management. The conclusion presents the results of the study.