Fernandao took advantage of poor defending to get one back for the visitors with 12 minutes remaining but Andres D’Alessandro restored Inter’s two-goal cushion three minutes later.
The home victory, Inter’s fifth straight, leaves them fourth in Brazil’s Serie A with 16 points from nine games. Bahia are seventh, two points behind.
Brazil’s league program will halt for a month from Thursday as the country hosts the Copa America.
Internacional maintained their 100% home league record on Wednesday when they beat Bahia 3-1 in their last game of the Brazilian campaign before it breaks for the Copa America.
Rodrigo Lindoso scored after 20 minutes and Rafael Sobis got a second just after the hour mark to put Inter in command.