Case series of urinary tract infection (UTI) in neonates (0 to 1 month of life) hospitalized in the neonatal care unit of Cagliari’s university hospital during a five-year period. The major findings of this study are the prevalence of the infections in the male sex, the very high sensitivity of leukocyte esterase in detecting UTI, a higher C reactive Protein (CRP) sensitivity and specificity in comparison with procalcitonin (PCT) among markers of pyelonephritis. Moreover E. coli demonstrated an elevated ampicillin resistance. The retrospective evaluation of the data has led to an improvement in preventive strategies and medical-therapeutic choices applied in our department for the management of UTI. In view of the lack of national and international guidelines for UTI in this specific period of life, our data will to contribute to establishing generally accepted treatment procedures in this age group.