There are many similarities between the Aztec and Inca cultures. Since both cultures were in power during the same time, and both located in the Americas, there is no wonder that each would share common traits.
Both the Inca and the Aztecs have similar origin myths. They both involve the original peoples traveling in search for the place to establish their city. In the Aztec version, there was a vision of an eagle perched on top of a cactus clutching a snake in its claws, and that is where they were to build their city.
In the Inca version, the people were instructed to build a temple to the sun god where a staff had sunken into the earth. Though slightly different, both stories are very similar in the fact that the people had to find a specific location to begin their cities.
The Inca and the Aztecs were both large, dominating empires of their regions. They would conquer neighboring city-states and then often placed the previous ruler back in power after establishing themselves as the presiding power. Each city-state continued to be politically individual, and the empire required taxes to be paid in goods and labor. The Aztec and the Inca both had armies that participated in ritual war and sacrifice.
Even though the empire mandated a state religion, the continuation of local culture was tolerated. An empire-wide language was also established, but each city-state also used their native languages. The Aztec and Inca cultures built pyramids with temples on the top.
The Aztecs and Inca both were involved in agriculture. They used fertilizers and irrigation to help their crops grow since neither culture lived in very fertile areas. For both, common crops included: corn (maize), tomatoes, chilies, cocoa, peanuts, sweet potatoes, and cotton. Dogs were domesticated by the Aztec and Inca. The empire maintained trade for goods that were locally unattainable.
The Aztec and Inca empires ended around the same time only about eleven years apart. The end of the Aztec empire was around the year AD 1521, and the end of the Inca empire was around the year AD 1532. This similar time for the fall of the empire is due to the Spanish Conquest of the Americas. The Spanish brought with them the smallpox disease, which proved to be a devastating epidemic for both the Aztec and Inca cultures. This made it easier for the Spaniards to take control, since many of the natives died due to smallpox.
From beginning to end, both the Aztec and Inca cultures have many similarities. Both were powerful empires in the Americas that shared aspects in government and agriculture.