US District Court Judge Sim Lake handed the case to the jury of eight women and four men shortly before 11 am local time (noon EDT) on Wednesday to decide whether the two men are guilty of fraud and conspiracy at the defunct energy company.
The panel, which began hearing the case at the end of January, was expected to choose a foreperson and agree on a schedule as its first order of business.
Lay, 64, and Skilling, 52, are charged with lying to investors to hide the financial turmoil at the company in the months before Enron collapsed in December 2001 into the then-largest ever US bankruptcy.
The two men have denied any wrongdoing and face decades in prison if convicted.
Sean Berkowitz, the assistant US attorney, told the jury as he concluded his final argument against the two men that "you get to decide whether they told truth or lies."
"I submit, ladies and gentlemen, that when you consider all the evidence you will conclude beyond a reasonable doubt that these men lied. They withheld the truth and they put themselves before investors. You can't buy justice"
assistant US attorney
"I submit, ladies and gentlemen, that when you consider all the evidence you will conclude beyond a reasonable doubt that these men lied. They withheld the truth and they put themselves before investors. You can't buy justice."
Skilling faces 28 counts of conspiracy, fraud and insider trading and Lay, 64, faces six counts of fraud and conspiracy linked to the downfall of the company they built into the seventh-largest company in the United States.
Lay also faces a separate trial that will begin on Thursday on four charges he misused bank loans to buy Enron stock. At Lay's request, that trial will be heard by Judge Lake without a jury.
Prosecutors contend that Lay and Skilling directed a conspiracy that hid billions of dollars in debt in dubious off-balance sheet deals, illegally shifted funds to hide losses at poorly performing units and tapped reserve accounts to impress Wall Street.
The government brought to the stand eight former Enron executives to testify against their former bosses.
The two former executives, who both testified in their own defence, said Enron was the victim of biased media reporting and a conspiracy of predatory investors to drive down its stock price.