The issue of whether private label and branded goods should be considered in the same market has been debated in competition cases for a long time. Traditionally, competition authorities have considered large price difference between branded and private label products as evidence that branded and private label products are in separate markets. We show that private label products should generally be considered in the same market as branded products in the same product group. For a first assessment, the competitive constraint from a private label product on branded products is well approximated by its market share in the product group. This means that private labels should always be included in the initial assessment of market definition in merger cases and for the purpose of determining critical market share thresholds when applying, for example, the Vertical Block Exemption Regulation.