The incidence of diseases has been increasing in the breeding of dairy cattle recently. The cost of treatment is constantly rising, and in addition, mastitis control programs are plagued by an increased incidence of less common bacterial and antimicrobial resistance. Following the Nordic countries, selection could be applied to the udder health characteristics. Applicable traits include the incidence of clinical mastitis, somatic cell count, udder conformation, and body condition. The aim of the study was the evaluation of the phenotypic impact of udder conformation traits and body condition score on the incidence of clinical mastitis and somatic cell count. The use of new skills in breeding could be reflected in the fertility, health, welfare, length, and quality of life of dairy cattle. Incidence of clinical mastitis and somatic cell count in milk was monitored in 17 622 first lactation Holstein cows. The incidence of clinical mastitis and the average somatic cell count was high at the beginning of lactation; around day 100-150 slightly decreased and then increased until the end of lactation. Skinny cows were more sensitive to outbreak udder inflammation in lactation. Cows with redundant fat coverage were also more diseased. Clinical mastitis is related to high metabolic load and fat breakdown with the incidence of metabolic diseases. Clinical mastitis and somatic cell count increased with increasing and decreasing of body condition score. There were proposed appropriate selection criteria for the selection of heifers. There were strong and tight Fore Udder Attachment, intermediate and shallower Udder Depth, high Rear Udder Height, deep Central Ligament, intermediate Udder Width, Middle of quarter Front Teat Placement, intermediate Teat Length, midpoint Rear Teat Placement, and intermediate Body Condition Score. Optimal measurement points are the same for optimal somatic cell count and clinical mastitis.