We have analyzed utrasonographic finding of 55 cases of hydronephrosis and 34 cases of renal maasses. Theresults are as follows; 1. 55 cases of hydronephrosis revealed renal enlargement in 55 cases, separation ofcentral echo complex in 27 cases, multiple anechoic areas radiating from the center in 25 cases and dilated renalpelvis in 24 cases. 2. Among the renal masses in 34 cases, simple renal cyst were 15 cases, polycystic kidney in 8cases, hypernephroma in 8 cases, Wilms' tmor in 2 cases and angiomyolipoma in 1 case. 3. Simple renal cystrevealed single in 14 cases (93%) and well defined anechoic mass with posterior enhancement in all cases. 4.Polycystic kidney revealed bilateral irregular shaped renal enlargement and multiple anechoic cysts throughout thekidney. 2 cases (25%) involved liver. 5. 6 cases (75%) of hypernephroma revealed ill defined modarately echogenicmass without posterior enhancement. 6. All cases of Wilms' tumor revealed well defined large mixed echogenic massin right kidney. 7. Angiomyolipoma revealed bilateral dense echogenic mass with large hemorrhagic cyst in rightkidney. 8. The ultrasonography is useful noninvasive diagnostic modality of evaluation of renal masses andhydronephrosis.