Depending on the site of obstruction to the urinary flow, the hydronephrosis may be unilateral or bilateral. A unilateral hydronephrosis occurs when the obstruction is above the level of the bladder. Causes may be present either outside the ureter, in the wall of the ureter or the lumen of the ureter. Ureteral obstruction with subsequent hydronephrosis is a common clinical occurrence. All relevant and routine investigations were done in these cases to establish diagnosis. Ethical clearance has been obtained from the institution for the same. All these patients were examined, evaluated & data was collected according to the proforma. In this study, 2 cases (2%) of the total study subjects had abnormal blood urea levels and 73 cases (98%) had a normal blood urea levels though they had various grades of hydronephrosis. In this study series of 75 patients, the p-value obtained in the comparison between the serum creatinine levels & the different grades of hydronephrosis was <0.001, which proves statistical significance