Abstract: Concrete slab with opening are usually designed with help of traditional rules of thumb proposed by building codes. Such methods however introduce limitations concerning size of opening and magnitude of applied loads. Furthermore there is a lack of sufficient information about the load carrying capacity of slab with opening. It is also difficult to model the complex behaviour of reinforced concrete structures analytically in its non-linear zone. This has led engineers in the past to rely heavily on empirical formulas which were derived from numerous experiments for the design of reinforced concrete structures. Nowadays, for structural design and assessment of reinforced concrete members, the non- linear finite element (FE) analysis has become an important analytical tool. This thesis investigates the structural behaviour of two way reinforced concrete slab with and without openings for different slab length ratios and different opening ratios. The effect of openings sizes on crack formation is also analysed. For this different models of slab with and without opening were modelled in finite element software ANSYS.