In this paper we study the problem of photoacoustic inversion in a weakly attenuating medium. We present explicit reconstruction formulas in such media and show that the inversion based on such formulas is moderately ill-posed. Moreover, we present a numerical algorithm for imaging and demonstrate in numerical experiments the feasibility of this approach. arXiv:1705.07466v1 [math.NA] 21 May 2017 R, appearing as a source term in the wave equationfrom some measurements over time of the pressure p on a two-dimensional manifold Γ outside of the specimen, that is outside of the support of the absorption density function. This problem has been studied extensively in the literature (see e.g. [14,25,13], to mention just a few survey articles). Biological tissue has a non-vanishing viscosity, thus there is thermal consumption of energy. These effects can be described mathematically by attenuation. Common models of such are the thermo-viscous model [9], its modification [11], Szabo's power law [22, 21] and a causal modification [10], Hanyga & Seredy'nska [5], Sushilov & Cobbold [20], and the Nachman-Smith-Waag model [15]. Photoacoustic imaging in attenuating medium then consists in computing the absorption density function h from measurements of the attenuated pressure p a on a surface containing the object of interest. The attenuated pressure equation reads as follows