As per local conditions and availability of materials different countries have adopted different methods for design of flat slabs and given their guidelines in their respective codes. The aim of this analytical study is to try and illustrate the methods used for flat slab design with and without column head using ACI-318, NZ- 3101 part 1,Eurocode part 2 and IS: 456- 2000 design codes. For carrying out this study an interior panel of a flat slab with dimensions 6.6 x 5.6 m and super imposed load 7.75 KN/m2were adopted.