For most construction works, engineers have to make holes for various utilities and services with different structural elements. The most critical holes are those in reinforced concrete columns, since the columns are the elements that carry the vertical loads from the floors to the foundation. In the current study, a numerical study of fourteen circular reinforced concrete columns (CRC) with one and two circular transverse holes (CTH) under both axial and non-axial loads is investigated. The circular RC columns have a diameter of 200 mm, a height of 1000 mm, six longitudinal reinforcement steel bars with a diameter of 12 mm, and stirrups with a diameter of 8 mm every 166.6 mm center-to-center spacing. A three-dimensional nonlinear finite element model is conducted using ABAQUS Simulia V.6.9 software to investigate the performance of CRC with 63.5 mm diameter CTH that having an area greater than 30% of column diameter under both axial and non-axial loads with different holed locations, 33%, 40%, 50%, and 67% of column height. According to the results, the presence of transverse holes significantly reduces load-carrying capacity, a reduction in ultimate strength ranging from 30% to 41% for columns subjected to axial load, and from 20% to 25%for columns subjected to non-axial load, depending on the number of holes and their location in all specimens. Finally, it was found that the decrease in strength for non-axial loading is much greater than for axial loading, with an average of 30%.