The extensive road system built by the Inca Empire was meant both to facilitate commerce and to allow rapid deployment of the army (similar to the Roman road system). A military action would be usually initiated by a military parade/exercise to awe the adversary. In case the opposing force would still be willing to fight, the general in command (or the Inca himself) would review the troops while musical instruments were played. After this, the commanding officer would rally the troops for the attack.

The Inca army military effectiveness was based in two main elements: logistics and discipline. In order to facilitate the movement of their armies, the Inca built a vast road system. Staging areas were set along the roads so the troops and the animals could rest, and the weapons could be readied. Discipline was very rigid as well.

Army squads were organized in the following manner: The front lines were initially occupied by slingshot bearers and archers, which would go to the rearguard of the formation after the initial barrages. The lines behind them were occupied by storm-troopers with clubs and axes, then short-spear bearers and closing the formation long-spear bearers (up to 6 meters long).

During an open-field battle, an Inca Army unit would usually be divided in three groups. The main group would frontally attack the opposing force while the other two would flank it and circle around it. Before the hand-to-hand combat would start, the Inca army would use ranged weapons (slingshots, arrows and short spears) in order to break enemy lines. On the opposite, most enemies in the region were poorly organized and would perform mass frontal charges after breaking formations. As a matter of fact, the Inca army was quite disciplined and would not frequently break lines, being able to effectively repel ambushes in jungle, mountain and swamp terrains. In the event that the opposing force would take refuge in a fortress, mountain or city, Inca forces would cut communication and supply lines. If negotiations failed, Inca forces would attempt to storm the fortress and/or starve the opposing force.

Occupied cities and their inhabitants were usually well-treated if they surrendered without resistance. According to the degree of resistance offered, the Inca would apply several punishments to the conquered population. The Inca could even authorize the complete annihilation of a city or ethnic group in the case of a rebellion (as was the case with the Pastos).

The Sapa Inca himself would rally the troops in large conquest campaigns, while for small rebellions, barbarian invasions, or small campaigns, a general or a prince would be sent in his representation.

A big advantage for the Inca army over its enemies was its numeric superiority. While adversaries used to be all warriors from a single tribe (or at the most, an alliance of several tribes), the imperial troops were masses of men from all over the empire. Thanks to the large scale of the empire, hundreds of thousands of warriors could be mobilized. This wide variety of men would prove both an advantage (numerical superiority and specialized soldiers for different terrains) and a disadvantage (lack of cohesion between army battalions). Both Inca oral histories and Spanish written accounts estimate the Incas could field armies of 100,000 at a time.