RATIONALE: Autosomal recessive polycystic kidney disease (ARPKD) is a severe rare genetic condition, with high mortality rates and autosomal recessive pattern of transmission similar to most early onset cystic kidney diseases. The mortality rates can reach up to 30% during the neonatal period. PATIENT CONCERNS: We report a case of a 27-day-old male neonate admitted in our clinic for fever, foul-smelling urine, and diarrhea. A previous abdominal ultrasound at the age of 2 weeks revealed enlarged, hyperechoic kidneys, no abnormalities of the urinary exam. Clinical examination revealed poor general status, ill-looking face, diminished cutaneous turgor, distended abdomen, and palpable kidneys. Laboratory tests pointed out leukopenia, anemia, border-line platelet count, elevated inflammatory biomarker level, hyponatremia, hypoalbuminemia, proteinuria, leukocyturia, and hematuria. Both urine and blood cultures were positive for E. coli. DIAGNOSES: Abdominal ultrasound revealed bilateral nephromegaly, diminished parenchymatous index, with the absence of differentiation between the cortex and medulla. Abdominal MRI described bilateral nephromegaly, the hypertrophy comprising especially the structures of Malpighi pyramids, with multiple cystic lesions disseminated within both kidneys, projected also in Malpighi pyramids, their diameters ranging between 2 and 7 mm. Thus, our final diagnoses were polycystic kidney disease and sepsis due to urinary tract infection with E. coli. INTERVENTIONS: After treating the infection, the patient was referred to a more experienced center for appropriate management of polycystic kidney disease. OUTCOMES: The progress of the patient until the age of 1 year and 2 months has been remarkably favorable, presenting first-degree chronic kidney disease, with normal blood parameters and controlled blood pressure values, no other episodes of urinary infection, and without supplementary pathological changes in ultrasound. LESSONS: Despite the poor prognosis of PKD reported in the literature, our case had an outstandingly favorable evolution during the first 2 years of life most-likely due to the early diagnosis and treatment, but also proper monitoring.