We present the discovery of two transiting exoplanets. HAT-P-28b orbits a V=13.03 G3 dwarf star with a period P=3.2572 days and has a mass of 0.63+/-0.04M_J_ and a radius of 1.21^+0.11^-0.08_R_J yielding a mean density of 0.44+/-0.09g/cm^3^. HAT-P-29b orbits a V=11.90 F8 dwarf star with a period P=5.7232 days and has a mass of 0.78^+0.08^-0.04_M_J and a radius of 1.11^+0.14^-0.08_R_J yielding a mean density of 0.71+/-0.18g/cm^3^. We discuss the properties of these planets in the context of other known transiting planets