In this paper both a hollow floor and the corresponding solid floor are analysed by using finite element software and the results are compared. The comparison is made through a detailed finite element study between a column-supported cast-in-situ hollow floor filled by tube with its solid counter-part. The orientation of the tube fillers causes the stiffness of the hollow slab to be orthotropic, potentially changing the distribution of load carrying between the two orthogonal directions. The inclusion of the hollows also potentially increases the flexibility of the slab. Recommendations for design of column-supported cast-in-situ concrete floors compared with the solid floor are then made with respect to distribution of design moments and calculation of deflections. Thus the reference was given to the designer.