In Turkey, the habit of making their own yogurt in people's homes is quite common. Some of these people stated that when they used commercial yogurt as inoculum during the yogurt making, they could not achieve the product with desired properties. This research aims to investigate the possibility of using the commercial yogurts as an inoculum source in yogurt manufacturing. For this purpose, four different yogurts were produced by using four different commercial yogurts as a first inoculum separately. The yogurt production was repeated four times by using the last yogurts obtained as an inoculum. The effect of 4‒generation yogurt production on some quality characteristics of yogurt was investigated. Moreover, first fermented yogurts were analyzed throughout 21‒day storage. Titratable acidity, pH, serum separation, viscosity, and Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus counts were analyzed. The technological parameters in four yogurt generations did not show a significant change. In this context, it was concluded that the use of commercial yogurts as the first inoculum did not adversely affect the subsequent fermentation process when the necessary hygienic and temperature conditions were maintained.