Experiments were carried out in conscious, chronically instrumented lambs (n=8) and young adult sheep (n=11) to investigate age-dependent renal responses to hemorrhage. Various parameters of renal function were measured for one hour before and one hour after either 10% hemorrhage (experiment one) or 20% hemorrhage (experiment two). The two experiments were carried out in random order at intervals of two to five days. There were no effects of 10-20% hemorrhage on RPF in either age group. BP decreased after 20% but not 10% hemorrhage in both age groups. GFR and FF decreased after 20% hemorrhage in both age groups, the decrease being greater in lambs than young adult sheep. In response to 20% hemorrhage, V and UNaV decreased by 40 min after hemorrhage in young adult sheep but not lambs and remained decreased for 60 min; UClV showed a similar response. In lambs but not young adult sheep, CH₂O increased by 20 min after 20% hemorrhage and remained above control at 60 min. UOsm decreased at 20 min after 20% hemorrhage in young adult sheep but not lambs, returning to control levels by 40 min. These data provide new information that renal responses to hypotensive hemorrhage appear to be developmentally regulated.