Continuous changing scenarios of software development technology make effort estimation more challenging. Some of the difficulties of estimation arise from the complexity and invisibility of software. Software development is intensively human activity and can't be free from error. Ability of ANN(Artificial Neural Network) to model a complex set of relationship between the dependent variable (effort) and the independent variables (cost drivers) makes it as a potential tool for estimation. The application of artificial neural networks in prediction of effort in conventional and Object Oriented Software development approach has been discussed.