We conducted a retrospective chart review of ten years of mother-neonate dyads at our centre with RBC mismatch to describe the type and frequency of maternal red blood cell (RBC) alloantibodies in our centre and newborn outcomes. Half of the 300 mother-neonate pairs had a total of 173 clinically significant maternal RBC alloantibodies. Rh antibodies were the most common, accounting for 67% (Anti-D accounting 10%) and thus continue to be the most prevalent clinically significant antibodies detected in maternal patients. Neonates born to women with all types of Rh alloimmunization were shown to require interventions to treat HDFN, including readmission.