In this paper, a digital pixel sensor in silicon on insulator (SOI) is presented. The active part is a partially depleted SOI phototransistor. The technique elaborated in Harik et al. (2008) [1] was designed and implemented. Moreover, we took advantage of some of the characteristics of the floating body SOI MOSFET to implement a first order delta sigma modulator in each pixel. Measured data show that the pixel has a sensitivity of 3 mW/m2 and a resolution of about 7 bits. This pixel can be operated in two modes: weak inversion (Idc=1.2 μA) and moderate inversion (Idc=15 μA). © 2010 Elsevier Ltd. All rights reserved.