The aim of the presented study was to analyze changes in milk composition depending on presence of genetically modified (GM) components in feed and according to cows’ age and lactation phase. The research was carried out with Polish Holstein-Friesian black and white cows (n = 50) housed in tie stall system at one farm. The genetically modified feed was a supplementary feed mixture. Data reports from milking trials with milk chemical composition, number of somatic cells and urea content were collected. The collected data concerned groups: primiparous (P) cows and multiparous (M) cows during 2nd and 3rd lactation. In each age group, two subgroups were distinguished: cows from 1st to 4th month of lactation (I) and cows from 5th to 8th month of lactation (II). The above subgroups were divided according to feed with GM components (G) and feed with non-GM components (N). It was found that use of feed with the addition of GM plants contributes to lowering the level of casein and an increase of lactose in milk. Presence of GM components in feed did not affect the level of fat, total protein, fat to protein content, urea levels, somatic cell counts in milk and cow yield. It can be concluded that the withdrawal of feed additives based on GM components does not adversely affect the technological quality of milk.