Zarate, considered along with rival Wilfredo Gomez to be among the best punchers in the history of boxing, and probably the two best punchers in the lighter divisions, had an amateur record of 33 wins and 3 losses, with 30 knockout wins, and he won the Mexican Golden Gloves, or Guantes De Oro, in 1969.
In 1970, Carlos made his professional debut with a 2 round knockout win over Luis Castaneda in Cuernavaca. That marked the beginning of a 23 fight knockout winning streak. The only boxers to get past the third round during that streak were Al Torres and Antonio Cataneda, who lasted 5 ad 9 rounds respectively, both at Tijuana. Victor Ramirez became the first boxer to last the distance with Zarate when Zarate beat him on points in January of 1974 in Mexico City over ten rounds. Next began his second 20 plus knockout wins in a row streak, when none of his next 28 opponents heard the final bell on their feet.
After knocking out former world title challenger Nestor Jimenez in two rounds at Mexicali to end 1975, the WBC made Zarate their number one challenger at the Bantamweight division. So, after beating Cesar Desiga by a knockout in four on March 29 of 1976 in Monterrey, Zarate was faced on the night of May 8 of that year with defending world Bantamweight champion Rodolfo Martinez in Los Angeles. Zarate became a world Bantamweight champion by knocking his countryman out in the eighth round. Zarate next won two fights by a knockout in the second and then defended it against Paul Ferreri, who lost by knockout in 12 in Los Angeles too. He finished '76 with a four round knockout over Waruinge Nakayama in a title defense held at Culiacan.
After beginning 1977 with a third round knockout win over Colombia's Fernando Cabanela in Mexico City, Mexican boxing fans started talking about a possible unification bout between him and fellow Mexican Alfonso Zamora, the WBA's world Bantamweight champion. Nicknamed by the American boxing press as The Z Boys, the two did square off, but not before much hassle and hurdle putting by boh the WBC and WBA, who wanted both boxers to pay a large amount of money before sanctioning the bout. So, the California state boxing commission decided to sanction it as a ten round, non title bout instead. Fans didn't seem to care that no world title belt would be involved that afternoon, and they packed the fight venue when Zarate and Zamora met in the LA suburb of Inglewood, on April 23 of '77. After a first round that featured a drunken man jumping into the ring to presumably attack one of the fighters, (and police intervention thereafter), Zarate proceeded to beat Zamora by a knockout in four rounds, and gain recognition by most boxing fans as the undisputed world champion of the Bantamweights. Then, he retained the WBC title with a knockout in six over Danilo Batista, and finished 1976 with a trip to Spain, where he retained the belt against challenger Juan Rodriguez, beaten in five.
In 1978, Zarate started out by meeting future world champion Alberto Davila, whom he knocked out in eight at Los Angeles to retain his belt. Then, in April of that year, he made his first of two trips to Puerto Rico that year, to fight challenger Andres Hernandez, who lasted until the 13rd. round at San Juan's Roberto Clemente coliseum. After retaining the title against Emilio Hernandez by a knockout in four and winning a non title bout, Zarate announced he was challenging the WBC's world Super Bantamweight champion, Gomez. According to many experts and the Ring Magazine book The Ring: Boxing In The 20th Century, Gomez and Zarate had the highest knockout win percentage of any two boxers paired inside a ring in history: When Gomez and Zarate met on October 28, also at Roberto Clemente Coliseum in San Juan, the challenger and still world Bantamweight champion Zarate was 55-0 with 54 knockouts, while defending world Super Bantamweight champion Gomez was 21-0-1 with 21 knockouts. Zarate went to the floor four times and tasted the sour taste of defeat for the first time in his career when he was beaten by a knockout in five rounds.
In 1979, Zarate made what would turn out to be his last successful defense, with a third round knockout win over Mensah Kpalongo in Los Angeles. After winning a non title bout against Celso Chavez by a knockout in five in Houston, Texas, Zarate met gym-mate Lupe Pintor in Las Vegas and lost a close 15 round decision. Enraged by losing a decision he thought he deserved, he announced his retirement from boxing and vowed never to fight as a professional again.
Zarate spent five years in retirement, but the temptation of the public adulation boxers receive when they become champions and the aroma of the boxing ring led him back into competition when he won a return bout in 1986 against Adam Garcia, winning a four round decision. 11 more victories in a row, all by knockout, including one over then number one world Super Bantamweight challenger Richard Savage (knocked out by Zarate in five in Mexico City), made him the WBC's number one challenger at the Super Bantamweight division once again.
And so, on October of 1987, he travelled to Australia to meet the man many Australian boxing fans consider to be the greatest Australian world champion of all time: Jeff Fenech. In a fight contested for Fenech's world Super Bantamweight title, Zarate lost by a four round technical decision. After Fenech vacated the title soon after to pursue the world Featherweight crown, Zarate and countryman Daniel Zaragoza met for the vacant world championship belt, but Zarate came back on the losing end once again, being knocked out in the tenth round and finally announcing his retirement for good.
Zarate had a nephew who went for a world title once in the 1990s: Joel Luna Zarate. During the '90s also, he became a member of the International Boxing Hall Of Fame, and recently, he and Gomez met at a boxing undercard in Puerto Rico to commemorate the 25th anniversary of their boxing bout.
He had a record of 66 wins and 4 losses as a professional boxer, with 63 wins by knockout.