SummaryBlood gas parameters and acid-base balance values were determined in adult pregnant New Zealand rabbits (Oryctolagus cuniculus) in standard laboratory housing conditions and during anaesthesia with an association of ketamine-chlorpromazine, administered before surgical procedures. All the variables were also studied in adult non-pregnant female, used as controls. No differences in pH, S02C, 02Hb, COHb, s02m and a-vD02 were found between pregnant and non-pregnant rabbits in physiologicalconditions and during anaesthesia. Ketamine-chlorpromazine and pregnancy seemed to change the other parameters used to assess the acid-base balance and the oxygenation conditions. Anaesthesia affected only Rb, 02et, 02Cap, CC02 and P50. The additive effect of pregnancy and anaesthesia modified pC02, p02, HC0 3 -, TC02, BEb, SBC, BEecf, A-aD0 2 , RI, MetHb, RHb, Ca02 and CV02' The patterns described are close to those of other species, suggesting the New Zealand rabbit might be a reliable animal model for monitoring selected variables.