Urinary tract is a frequent location of infection among children, this also applies to neonatal period. The prevalence of urinary tract infections (UTI) ranges from 0.1% to 1% among newborns born on time with a normal weight, about 10% among patients with a low birth weight and 4 to 25% in premature newborns. There are several defence mechanisms protecting against the development of UTI. The most significant microorganisms responsible for developing UTI among neonates are: Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Staphylococcus aureus, Enterococcus spp., Proteus spp., Streptococcus agalactiae, Chlamydia trachomatis and Candida albicans. Chlamydia trachomatis is also playing an important role in these kind of infections. The most frequent is occurrence of E. coli. In the neonatal period UTI is usually hematogenous or developed by the continuity of the reproductive tract of the mother. Nosocomial infections are also play a significant role in spreading microorganisms in this age group. Diagnosis UTI among newborns is difficult because of the nonspecific clinical representation. The course of the disease can vary from asymptomatic and mild to very severe and fully-blown. The diagnostic process should include markers of inflammation (i.e. leukocytosis, C-reactive protein and OB), urinalysis, urine culture and abdominal sonography. Other advanced diagnostic methods such as voiding cystourethrography and renal scintigraphy are chosen individually. Popularity of prenatal ultrasound tests has resulted in earlier detection of urinary abnormalities that constitute 20% of all birth defects. Antibiotics are a treatment of choice in urinary tract infections among neonates.