The effects of Co, Zr, Nb, Ga and Dy additions upon the magnetic properties of PrFeB-based alloys have been studied. Bonded magnets have been prepared from as-cast and homogenised alloys using an optimised hydrogenation disproportionation desorption and recombination (HDDR) process. In general, the HDDR bonded magnets from homogenised alloys exhibited higher remanence (B r ), squareness factor (SF) and intrinsic coercivity ( i H c ). In particular, the Pr 1 3 . 7 Fe 6 3 . 5 Co 1 6 . 7 B 6 Nb 0 . 1 HDDR magnet exhibited the best overall magnetic properties (B r =1032+/-20 mT, i H c =793+/-20 kA/m and SF=0.51), indicating that Co and Nb additions, in these proportions have a beneficial effect on PrFeB-based magnets. Conversely, additions of Ga and Dy were observed to dramatically reduce the intrinsic coercivity of Pr-based HDDR magnets.