The company, which is controlled by the family of billionaire Carlos Slim, said profit in the July-September period fell to 10.12 billion pesos ($754 million) from 16.38 billion pesos a year earlier.
Analysts had expected the company to report a net profit of 16.47 billion pesos, according to a Reuters poll.
America Movil's tax burden rose by 4.43 billion pesos versus the same quarter last year, while the cost of sales rose 16.157 billion pesos.
Revenue rose 14 percent to 220.884 billion pesos, principally due to the consolidation of Telekom Austria, of . . .