A connector comprising a needleless access device and a backflow check valve for transferring fluids and method therefor. The connector may have a first port, a second port, and a third port. A first valve element may be positioned within the first port and a second valve element may be positioned within the second port. The first valve element may be in a first position as a first fluid flows between the first and third ports. The second port may be used to introduce a second fluid into the connector. Upon introduction of the second fluid to the connector, the first valve element may move from the first position to a second position. In the second position, fluid may be prevented from flowing past the first valve element.