Genetically engineered cell therapies are emerging platforms that have the potential to address unmet clinical needs. Several strategies have been developed for inserting a gene of interest into the target cell, including novel direct DNA and RNA delivery methods. However, viral-based vectors have so far remained the primary platform for these key transductions. The increasing number of products being registered for clinical trials in recent years has created a need for viable Good Manufacturing Process (GMP) vector production. Here we focus on challenges and new developments in purifying vector products at scales that are suitable for cell and gene therapy treatments.