In this paper, the calculation of transients on a multiwire line is performed using the finite element method, including the frequency dependence of the parameters of the multiwire line. The multiwire line has been a subject of interest for a long time. Therefore, a review of the most famous methods for calculating transients on a multiwire line is an integral part of the dissertation. High-quality input data, i.e. frequency-dependent parameters of the multiwire line, are necessary for testing numerical models. Therefore, the paper also includes some methods for calculating frequency-dependent parameters of a multiwire line, including frequency scanning, which can also be used for frequency analysis of more complex systems, e.g. parts of electrical networks. Numerical modeling of electromagnetic transients on a multiwire line with frequency-independent parameters using the finite element method in the time domain is a kind of introduction to the main part of the dissertation. This model is the starting point from which a new numerical model of a multiwire line with frequency-dependent parameters was obtained. The derivation of a new mathematical finite element model of a multiwire transmission line, including the frequency dependence of the parameters, is the central part of the dissertation. Frequency dependence is achieved by including the convolution calculation in the system of finite element equations of a multiwire line. Based on the presented model, a computer program for the calculation of electromagnetic transients on a multiwire line in the MATLAB programming environment was developed. Finally, selected numerical examples were solved using the finite element method with frequency-dependent parameters. The correctness of the presented numerical model was proven by comparison with solutions from the literature and by using other computer packages for transient analysis. The original scientific contribution of this work is the development of a new numerical model for the calculation of electromagnetic transients on a multiwire transmission line based on the finite element method in the time domain with frequency-dependent parameters included.