This study presents an intelligent stethoscope that can visualize heart sound signals and can simultaneously measure human's electrocardiogram (ECG) and heart sounds. The proposed stethoscope can be used in hospitals and telemedicine through an internet of things (IoT) system and a cloud database. The proposed stethoscope includes three parts, namely, a front-end device for ECG and heart sound measurement, a smart device application (APP), and a cloud server. The ECG-measuring device is designed for single lead measurement and has low power consumption and IoT-based design, which can send real-time ECG data to the smart device APP. Simultaneously, the heart-sound-measuring device combined with a traditional stethoscope head is used to measure heart sound signals. This device includes an analog front-end circuit and a microphone to filter environmental noises and to record heart sound signals. Heart sound signals are transmitted to the APP by using a Bluetooth Low Energy module. The smart device APP can display synchronized and real-time signals, including ECG and heart sounds. Meanwhile, those signals are recorded in smart devices and are uploaded to the cloud server, where doctors and users can diagnose and monitor healthcare anytime. The cloud server can store previous signals and can realize telemedicine through a web user interface. The proposed intelligent stethoscope is applied on human trials in the National Cheng Kung University Hospital.