The United States, the European Union and major Latin American countries have criticized Sunday's vote in which leftist President Nicolas Maduro is likely to win re-election to a six-year term.
Critics say Maduro, a 55-year-old former bus driver who has presided over an economic meltdown, is virtually assured victory as two of his most popular opponents are banned from running and the electoral council is pro-government.
The Trump administration has threatened further sanctions and urged Latin America to cut off Venezuelan officials from financial systems and restrict their travel visas.
Any foreign shows of support are especially welcome to Maduro in the run-up to Sunday. On the campaign trail he has sought to legitimize his leadership, while playing down the brutal economic crisis that has Venezuelans skipping meals, succumbing to once controlled diseases, and emigrating en masse.
In a split screen chat broadcast on Venezuelan state television on Thursday, Maduro and Erdogan held a stilted, translated conversation that had several technical problems.
"I have faith you will be triumphant," Erdogan told Maduro, whose main rival is former state Governor Henri Falcon, who broke with an opposition boycott to run for the presidency.
In turn, Maduro told Erdogan "Venezuelans are going to give a lesson on democracy and liberty to the world on Sunday."