The objective of our study was to assess the prevalence of subclinical mastitis and the knowledge of risk factors in ninety-two dairy farms in the wilaya of Skikda. Screening results revealed that 404 dairy cows (67.2%) had subclinical mastitis; while 1055 quarters (44.8%) tested positive for CMT. It should be noted that this prevalence of subclinical mastitis is predominant at the end of lactation on the one hand and that the posterior quarters have the frequencies of the highest positive scores compared to the anterior quarters on the other hand. The results of the CMT test indicate a high prevalence of subclinical mastitis in the study area. This finding reveals both factors related to the animal (stage and lactation rank, breed) and factors related to the animal’s environment (hygiene of housing and milking dairy cows and maintenance of milking equipment). Screening for subclinical mastitis must always be an integrated action in the health plan of dairy farms.