The aim of this study was to investigate caesarean operation (CO) undertaken before the pre-partum decrease of progesterone but following administration of a progesterone receptor antagonist and to evaluate the innocuity of this procedure for the dam and pups. Thirty seven bitches of 15 different breeds, received an injection of 15 mg/kg aglepristone 59 or 60 days after the estimated day of ovulation, determined by progesterone quantitative assays, and caesarean section (CS) was performed between 20 and 24 h after administration. Progesterone remained above 6 nmol/l at the time of CS (mean = 15.75, SD = 3.84). No post-operative clinical complications were reported in any of the bitches. All bitches were able to nurse and feed their puppies in the first 24 h following surgery. No pups showed any signs of prematurity and 5 out of 188 pups (2.6) died in the first 2 weeks after delivery. This small study demonstrates that a CS may be safely and successfully performed an average of 2 days before the expected date of parturition following the administration of aglepristone, without any harmful consequence for the dam and her neonates.