The paper analyzes various classification techniques in data mining, specifically focusing on Bayesnet, Naive Bayes, and J48 classifiers using the Weka tool to evaluate their performance on two datasets: breast cancer and sick data sets. Performance metrics such as mean absolute error, root mean-squared error, and model building time were used for comparison, revealing that while J48 performed best overall, Naive Bayes uptable was the fastest. The study concludes that no single classifier is universally superior and suggests future exploration of additional classifiers in Weka.