Twenty five numbers of crossbred pig foetii were selected based on their crown-rump length and subsequently divided into 5 age groups consisting of 5 animals in each group viz. group I (41-55 days), group II (56-70 days), group III (71-85 days), group IV (86-100 days) and groupV (101-114 days). No renal pelvis was evident in group I in all the kidneys under study. From group II onwards, the renal pelvis was distinct and extensive with a well developed ureter that originated from the middle of the pelvis in both the kidneys