This work is to suggest an IP based Patient Monitoring System (PMS) with an Open Architecture Approach Theory (OAAT). The PMS is based on latest buses connectivity, especially by using the TCP/IP protocol suite as an internal bus instead of the traditional design like HPIB, Profi-bus and CAN bus etc. The TCP/IP protocol suite is easily available in very cheap price, so it is good approach to use TCP/IP protocol suite as internal bus for reducing the cost effectiveness. The TCP/IP protocol suite based architecture systems are capable to upgrade the PMS’s firmware and software through dedicated TCP/IP protocols suite via open communication network.