In this paper, we propose a new intelligent prediction system to predict more accurately the presence of heart diseases effectively from feature-selected medical dataset. For this purpose, a new weighted genetic algorithm is proposed for selecting very important features from the dataset for improving the prediction accuracy of the disease. In this proposed intelligent prediction system, the data are preprocessed using the new weighted genetic algorithm and the new weighted fuzzy C-means clustering algorithm is used for effective fragmentation. Finally, we have used the ID3 algorithm for classification which is useful for making effective decision.