Abstract-To find an efficient and valid alternative of polysomnography (PSG), this paper investigates real-time sleep apnea and hypopnea syndrome (SAHS) detection based on electrocardiograph (ECG) and saturation of peripheral oxygen (SpO 2 ) signals, individually and in combination. We include ten machinelearning algorithms in our classification experiment. It is shown that our proposed SpO 2 features outperform the ECG features in terms of diagnostic ability. More importantly, we propose classifier combination to further enhance the classification performance by harnessing the complementary information provided by individual classifiers. With our selected SpO 2 and ECG features, the classifier combination using AdaBoost with Decision Stump, Bagging with REPTree, and either kNN or Decision Table achieves sensitivity, specificity, and accuracy all around 82% for a minute-based realtime SAHS detection over 25 sleep-disordered-breathing suspects' full overnight recordings.Index Terms-Classifier combination, electrocardiograph (ECG), feature selection, hypopnea, machine learning, saturation of peripheral oxygen (SpO 2 ), sleep apnea.