In an appointment-making method for a user's mobile device, a request for an appointment with a doctor is transmitted by the mobile device. Information as to doctors and services available for patient registration therewith is obtained and transmitted to the mobile device. A confirmation response from user's mobile device is received, and an appointment with a doctor is fixed. A registration number is assigned to the user in response to the received confirmation response. According to the assigned registration number, a patient queue for the doctor or the department is established, based on a predefined queue algorithm. Data as to queue length associated with the registration number is transmitted to the mobile device and payment of medical fees can also be made through the mobile device.