In this paper we report on both the DC and low frequency noise (LFN) properties of InP/InGaAs heterojunction bipolar phototransistors (HPTs) featuring waveguide type illumination. Both DC and LFN measurements demonstrate the good quality of these devices. In particular, they exhibit a 1/f noise figure-of-merit of 2.10(-8) mu m(2), which is exceptionally very good in the field of the compound semiconductor HBTs, where values around 10(-7) mu m(2) are usually reported.