This thesis is concerned with the use and development of mass matrices. A literature study is performed to determine the role of the mass matrix in the current state of the art of dynamic structural analysis. For simplicity and efficiency, the information obtained from the literature study is presented in a tabular format. A comparison study of three different types of mass matrices on the basis of frequency prediction is conducted. In order to perform the comparison study, a computer code was developed using beam-column elements to assemble the system mass matrix and calculate the eigenvalues and eigenvectors. This code was then added to the code developed in CE4002 - Matrix Structural Analysis and CE5980 - Computer Aided Structural Design. Test problems are presented and comparisons made with exact solutions and solutions from the literature. / Master of Science