Acute Lobar Nephronia (ALN) is a rare infective condition of the kidney currently described only in case reports and small case series. The diagnosis of ALN is made by characteristic clinico-radiological findings. Differentiation from acute pyelonephritis, renal abscess and renal tumor is crucial for proper management and to avoid unnecessary diagnostic interventions. Herein, we report a 58-year-old woman with an uncontrolled diabetes mellitus, who was diagnosed clinically as acute pyelonephritis and treated with standard duration of antibiotics but had recurrence of symptoms. On evaluation, she was found to have ALN which was treated successfully with prolonged antibiotic course.