Abstract: With the objective to evaluate the efficiency of the Controlled Intravaginal Devices Releasing (CIDR) new and reutilized until a 4th occasion and their effect on the pregnancy rate were studied 594 Brahman multiparous cows with their calves with 468.4±33.9 kg of body weight and with a minimum of 90 days postpartum and Fixed Time Artificial Insemination (FTAI) under humid tropical conditions. The cows were randomly assigned to one out to 8 treatments where the CIDR1A was new and anestrous cows; CIDR1C: new and cyclic cows; CIDR2A: Second use and anestrous cows; CIDR2C: Second and cyclic cows; CIDR3A: Third use and anoestrus cows CIDR3C: Third use and cyclic cows; CIDR4A: Fourth use and anestrous cows; CIDR4C: Fourth use and cyclic cows in the following way T1 (n = 116): CIDR1A+estradiol benzoate (E)+D-Cloprostenol+eCG+AI at detected estrus; T2 (n = 34): CIDR1C+E+D-Cloprostenol+AI at detected estrus; T3 (n = 53): CIDR2A+E+D-cloprostenol+eCG+Fixed Time Artificial Insemination (FTAI); T4 (n = 62): CIDR2C+E+D-Cloprostenol+FTAI; T5 (n = 33): CIDR3A+E+D-Cloprostenol+eCG+FTAI; T6 (n = 67): CIDR3C+E+D-Cloprostenol+FTAI; T7 (n = 41): CIDR4A+E+D-Cloprostenol+eCG+FTAI and T8 (n = 188): CIDR4C+E+D-Cloprostenol+FTAI. The pregnancy rate was different among treatments being 35.3, 61.7, 30.1, 64.5, 21.2, 82.0, 41.4 and 48.9% for T1-T8, respectively. In conclusion, the use of new or reutilized CIDR up to a 4th time plus artificial insemination at fixed time in Brahman cows represents an alternative to synchronize estrus and ovulation to improve gestation percentages.