Abstract: The mental state of a person is judged by detecting smiles. The smile detection starts with face recognition. Our paper accurately detects a face in an image, identifies the persons mouth, and determines if they are smiling or not. Given a set of images of a person entry in our system, we can compare these images using algorithms to detect face and to detect automatically the corners and the features of the mouth, then we determine which picture has the best smile. This method was robust and gives us the best result to detect the best smiling face from the database that contains 200 images. Keywords: Face Detection, Smile Detection, corner detection, Haar Classifier.