Carlos Montaldo was an Argentine rower who represented Club de Regatas San Nicolás. During the 1960s Montaldo often rowed with compatriot Ricardo Durán in the coxless pairs at international regattas. In 1963 the pair won bronze in the event at the Pan American Games in São Paulo. One year later they competed at the 1964 Tokyo Olympics where they finished third in their repêchage heat, but did not start in the B Final. Montaldo later served as a member of the San Nicolás rowing club’s sub-committee.