Aspects about the numerical modeling of three-dimensional prestressed steel-concrete composite beams by using the finite element (FE) method are highlighted and commented in this work. Emphasis is given to the numerical treatment of bonded and unbonded tendons. The proposed modeling technique uses curved beam and catenary elements for simulating internal and external tendons, respectively. Other issues such as the constitutive model for shear connectors, steel beam and concrete are also discussed. Several numerical examples with experimental and numerical results are presented. It is encountered that a faster numerical convergence is achieved when the tendon stiffness is included in the overall stiffness of the structure, even when the unbonded internal situation is addressed. Moreover, omitting slipping at the deviator device may lead to inaccurate results in the evaluation of tendon forces for external prestressing. Favourable agreement is encountered for all studied examples.