A hydraulic pressure supply system of an automatic transmission for a vehicle may include a hydraulic pump receiving oil stored in an oil pan through an input line, generating hydraulic pressure, and discharging the generated hydraulic pressure in the oil through a low-pressure discharge port and a high-pressure discharge port, a first switch valve switching a first switch hydraulic line in order to supply the hydraulic pressure discharged from the low-pressure discharge port of the hydraulic pump selectively to the low pressure portion or the high pressure portion, a second switch valve switching a second switch hydraulic line in order to selectively supply the hydraulic pressure supplied from the first switch valve to the low pressure portion or to return the hydraulic pressure supplied from the first switch valve to the oil pan, a low-pressure regulator valve, and a high-pressure regulator valve.