Mastitis is the inflammation of the mammary gland and udder tissue, and represents a major endemic disease of dairy cattle. It occurs as an immune response to bacterial invasion of the teat canal by variety of bacterial sources present on the farm or as a con-sequence of chemical, mechanical, or thermal injury to the cow’s udder. There is sometimes permanent damage to the udder. Severe acute cases can be fatal and lactations may be compromised despite of the apparent recovery of the mammary tissues. This condition is a very complex disease affected by several factors and it is usually presented subclinically in herds. Mastitis treatment and control supposes large costs to the industry and there are lots of losses due to this illness (reduction in yields, milk thrown away, extra labour, veterinary care and medicines, reduced longevity). In accordance with the current situation, an updated review has been carried out using graphic resources such as photos, tables, flowcharts, etc. The author, a specialist in this field, has developed an accurate handbook analyzing the most highlighted features of this condition and pointing out the main control measures to prevent it as maximum as possible. An interesting chapter referred to case investigation has been included to illustrate this topic in a more practical way.