Unilateral renal agenesis (incidence of 1/500–1000 newborns), can be isolated or associated with other urological/extra-urological abnormalities. Unilateral renal agenesis (URA) may be suspected after a renal US and confirmed by static renal scintigraphy. We describe 3 cases among the 1299 children born in our Centre in the first half of 2015. S., born at 40 weeks, eutocic delivery. APGAR 8/9, weight 3350 g. In the third day of life a diagnosis of situs inversus viscerum totalis, subaortic stenosis, restrictive ventricular septal defect and atrial septal defect ostium secundum has been made. In the fourth day of life, abdominal US findings were suggestive of right renal agenesis. The patient underwent cystography, negative for reflux, and static renal scintigraphy which confirmed diagnosis. Renal function, cerebral US, audiologial assessment and karyotype were normal. M., born at 27,5 weeks by C-section, APGAR 6/8, weight 1240 g. Mother with gestational diabetes. In the first day of life, patent ductus arteriosus and patent foramen ovale were detected. After 2 months US before discharge revealed right renal agenesis. Cystography was negative and renal scintigraphy confirmed diagnosis. B., born at 34,6 weeks by eutocic delivery. APGAR 7/8, weight 2240 g. As an imperforate anus was detected, the patient underwent renal US which revealed pyelectasis and empty left renal space. Diagnostic management was incomplete because the patient was transported to another Health Care Centre.