Congenital rubella syndrome (CRS) is of substantial concern due to the potential for intrauterine fetal demise and devastating birth defects like deafness. CRS is a result of the trans-placental transit of rubella virions during maternal rubella infection, which can be prevented through widespread vaccination against rubella. Rubella-containing vaccines (MMR and MMRV) are routinely administered to Canadian children in a two-dose schedule, which grants sufficient immunity in most of the population. As such, the National Advisory Committee of Immunizations (NACI) does not recommend any further immunization against rubella beyond two lifetime doses. These live vaccines are contraindicated in pregnancy and instead are administered after birth in susceptible mothers. Recent changes in the standard of care require a review of the vaccination history prior to administration of MMR or MMRV to post-partum mothers, as two prior lifetime doses satisfy the NACI criteria for sufficient rubella immunity regardless of serology. The purpose of this quality improvement project was to assess for redundancy of rubella immunization on post-partum wards in Women’s Hospital, Winnipeg and estimate the associated annual cost. A 3-month audit period yielded 16 instances of MMR administration, two of which were redundant based on two prior lifetime doses. The act of observation itself is thought to have acted as an intervention to reinforce previous education about redundant MMR vaccination, with rapidly declining redundancy after the first month. If not for this improvement, a $615 - $733 expense in addition to 4 -5 hours of nursing labour would have been expected annually.