The non-stoichiometric sulfide pyrrhotite (Fe(1-x)S), common to many nickel ores, occurs in a variety of crystallographic forms and compositions. In order to manipulate its performance in nickel processing operations either to target the recovery or rejection or pyrrhotite, one needs an understanding of pyrrhotite mineralogy, reactivity and the effect this may have on its flotation performance. In this study, a non-magnetic Fe9S10 pyrrhotite from Sudbury CCN in Canada and a magnetic Fe7S8 pyrrhotite from Phoenix in Botswana were selected to explore the relationship between mineralogy, reactivity and microflotation. Non-magnetic Sudbury pyrrhotite was less reactive in terms of its oxygen uptake and showed the best collectorless flotation recovery. Magnetic Phoenix pyrrhotite was more reactive and showed poor collectorless flotation, which was significantly improved with the addition of xanthate and copper activation. These differences in reactivity and flotation performance are interpreted to be a result of the pyrrhotite mineralogy, the implications of which may aid in the manipulation of flotation performance.