The five allegedly sought out poor people willing to sell their kidneys for between $6,000 and $20,000, to be purchased mostly by Israelis, and also European clients, willing to pay as much as $100,000 each.
Surgeries to remove the organs were allegedly carried out in some of the many private clinics in Costa Rica that each year attract thousands of foreigners for cheap medical tourism.
The trafficking ring was broken up in 2013.
The trial is expected to run through November 30, with a bench of three judges deciding the verdict.
According to the prosecution, the ring was led by doctor Francisco Jose Mora Palma, head of the nephrology unit dealing with kidney diseases at the public Calderon Guardia Hospital in San Jose.
The Greek man, Dimosthenis Katsigiannis Karkasi, was accused of operating from his pizzeria near the hospital to find potential organ “donors” with financial problems and linking them up with the doctors in exchange for money.The other three doctors accused are urologists Fabian Fonseca Guzman and Massimiliano Anunzia Mauro Stamati, and peripheral vascular specialist Victor Hugo Monge.
The alleged ring was busted in 2013 with the arrests of the five men, who were suspected of having illegally carried out 14 kidney transplants.
Prosecutors were to call on 25 witnesses to substantiate their case — including a former policewoman who was said to have worked with the ring after selling her own kidney, and who was willing to give evidence against the five accused.
If convicted, the doctors and Katsigiannis Karkasi risk prison for the traffic of persons.
For the pizzeria owner, that could be six to 10 years behind bars. For the doctors, because the charges involve abusing their professional status to commit a crime, the sentences could be eight to 16 years.
The New York Times reported in 2014 that Israel had a lively underground kidney market, partly because of Jewish religious strictures that see organ donations by the deceased as a desecration of the body.