We evaluated nine patients, age 1 day to 17 years, having infantile polycystic kidney disease (IPKD). Using modern scanners with 5-MHz transducers we have observed two previously unemphasized sonographic (US) findings, a peripheral zone of normally echogenic cortex (five patients), and mild caliectasis (two patients). Our data suggest that IPKD is a more heterogeneous condition clinically and sonographically than generally appreciated and that presence of a thick normally echogenic renal cortex is a good predictor of concurrent normal renal function and prolonged survival.