The aim of the research was to evaluate the sources of financing agricultural activities in farms specialized in milk production. The subject of research was a group of family farms located in the Podlaskie and Mazowieckie voivodeships (provinces). The criterion for farm division was the number of cows in the basic herd. There was also an assessment of the most important factors conducive to the development of dairy farms. To do so, the opinions of dairy farmers were used, and their views in this regard were expressed on a five-point Likert scale. The research was conducted on a sample of 100 farms in 2021. The interpretation of the results was made in relation to the criterion adopted in the division of farms into quartiles. It was found that the main source of financing activities in dairy farms was own funds. The highest share of farms using commercial loans was in the group of farms with the largest number of cows. With an increase in the number of cows in a herd, the area of farms increased, which is understandable due to the need to produce roughage. The most important factors influencing the development possibilities of agricultural holdings were the uninterrupted collection of raw material and a stable milk purchase price, which guaranteed the farmers’ financial liquidity.