The 60-year-old senator, his 56-year-old spouse Beatrice and Dr. Obinna Obeta, 51, were convicted of conspiring to exploit David Nwamini.
They will be sentenced on May 5 and could face up to 10 years in jail.
The trio were found guilty by the United Kingdom (UK) Magistrate's Court of trafficking Nwamini from Nigeria to Britain to provide a kidney for Ekweremadu's 25-year-old daughter, Sonia, a statement from the Crown Prosecution Service (CPS) said yesterday.
Sonia was cleared of the same charge for which her parents and the Nigerian doctor were convicted.
Sonia, who had declined to give evidence, broke into tears as she was cleared by the jury.
She tearfully hugged her father who was remanded into custody with the others ahead of the May 5 sentencing.
The prosecution confirmed that the maximum sentence in the organ harvesting case is one of life.
After the convictions, Chief Crown Prosecutor Joanne Jakymec, described the conspiracy as a horrific plot.
She said: “This was a horrific plot to exploit a vulnerable victim by trafficking him to the UK for the purpose of transplanting his kidney.
“The convicted defendants showed utter disregard for the victim's welfare, health and well-being and used their considerable influence to a high degree of control throughout, with the victim having a limited understanding of what was really going on here.”
The jury deliberated for nearly 14 hours to convict Ekweremadu, Beatrice and Obeta.
A detective inspector with the Metropolitan Police, Esther Richardson, commended the victim for his bravery in speaking against the offenders.
According to her, the police, the Crown Prosecution Service and Human Tissue Authority teams “worked tirelessly” on the case, which is the first time that defendants have been convicted under the Modern Slavery Act of an organ-trafficking conspiracy.
The Ekweremadus and Dr. Obeta denied the charges against them.
Ekweremadu had been in custody since June 23, last year. His wife, who was arrested with him, was granted bail by a criminal court in London, shortly after their arrest.
Nwamini, a street trader from Lagos, was taken to the UK last year to provide a kidney to Sonia in an £80,000 private transplant at the Royal Free Hospital in Camden, North London.
He claimed he was told to pretend to be Sonia's cousin to get the transplant approved.
But a consultant working in the NHS hospital refused to remove the vital organ, having become suspicious because the volunteer kidney donor appeared initially ignorant of his mission.
Nwamini reportedly told police investigators he had no idea his kidney was to be removed until he was taken to the Royal Free to meet the surgeon.
He ran away, sleeping on the street for about three days, before walking into the Staines Police Station on May 5, 2022.
Ike Ekweremadu, accused of organ harvesting, will remain in custody as the court adjourns until October.