Prematurity is defined by gestational age, estimated from the beginning of the woman's last Prematurity is defined by gestational age, estimated from the beginning of the woman's last menstrual period to the day of the delivery. Normal gestational age is agreed to be 40 weeks, therefore all newborns born before 37th gestational week are considered preterms or preemies. While evaluating the maturity of preterms, birth weight is also considered. Physiological and anatomical differences in preterms and their fuctional immaturity, which expresses more as the GA and BW are lower, can cause more difficult adjustment to extrauterine life and, consequently, more complications. Even though the advances made in the field of intensive care, new therapeutic approaches and implementation of evidence-based medicine in the clinical practice lead to lower mortality rates in preterms, the variability of complications that can arrise is still extensive. Neurodevelopmental difficulties and chronic illnesses are identified to be the most prominent complications in preterms, considering their incidence affects one's the quality of life both health-wise and socioeconomically. Their understanding in prematurely born children and adults alike lead to significantly better approach and care of those patients. Observing and implementing data about prematurity, as well as gestational age, as an independent risk factor proved to be very useful to primary care physicians, both family medicine and pediatrics specialists,as well as physicians working in secondary and tertiary medical centres, in order for complete diagnostic and therapeutic patient care to reach its full potential.