An access port for use in single port surgery includes a cannula to provide minimally invasive access to a surgical site and an instrument guide that fits closely within the cannula. The instrument guide includes guide channels that are open to the outside surface of the instrument guide. Each of the guide channels is configured to support a single surgical instrument at a defined position within the cannula. The guide channels may be smoothly enlarged at the end that receives surgical instruments. The access port may further include a seal that couples the instrument guide to the cannula such that the seal retains a pressurized insufflation fluid within the surgical site. The instrument guide may include one or more insufflation channels for introducing an insufflation fluid to the surgical site. The access port may include a flexible section. The surgical instruments may be controlled robotically by servo actuators.