Neonatology is a field of medicine specialized in care and treatment of various pathological and emergency conditions of newborns. The neonatal period is based on the complete dependence of the newborn on the mother due to the incomplete developtment of the neurological system of pediatric patients including vision, hearing and spinal reflexes. The neonatal period in puppies is one of the most risky periods in the life of an individual, which is manifested by as much as 11-13% of neonatal mortality. In veterinary medicine, the term newborn includes puppies from birth to 2 weeks of age, while the term pediatric refers to puppies between 2 weeks and 6 months of age. Puppies up to 12 weeks of age often get sick and represent a difficult challenge to clinicians. The reason for this is the unique physiological, biochemical and hematological differences between newborns and adult dogs. It is the understanding of emergencies in neonatology and the knowledge of the differences in the diagnosis, monitoring and treatment of critically ill neonatological patients compared to critically ill adult dogs that enables veterinarians to achieve the maximum survival rate. Specifics of physiological findings in pediatric patients include: low blood pressure, decreased heart rate, increased cardiac output, increased heart rate, lower body temperature, increased number of breaths per minute, decreased glomerular filtration capacity, heart murmur up to 6 months of age and many hematological and biochemical specificities. The newborn needs to undergo a detailed physical examination for the purpose of early detection of pathological and life-threatening conditions. In doing so, the veterinarian is able to react promptly and thus increase the newborn's chance of survival. During intensive care of neonatological patients, the greatest attention is given to the 4H principle, which refers to the monitoring of hypoxia, hypothermia, hypoglycemia and dehydration. Breastfeeding is the main source of nutrition for newborns where colostrum provides passive immunity, energy and nutrient intake. Colostral antibody transfer is of paramount importance because of the endotheliochorial type of placenta that allows minimal antibody transfer to the dog fetus. It is very important that puppies receive colostrum within the first 24 to 72 hours after birth because after 24 hours there is no absorption in the intestines due to changes in intestinal pH, proteolytic enzymes and loss of specific receptors. Drug metabolism in neonates differs greatly from metabolism in adult dogs. The reason for this is immature renal and hepatic mechanisms, differences in the amount of body fat, total protein and albumin.