Europol announced that eight nations co-operated in the operation. In Spain, 65 people face a series of charges relating to public health, money laundering and animal abuse.
Spain’s Civil Guard said that the criminal ring acquired horses in Spain and Portugal that were “in poor shape, old, or had been designated ‘not apt for consumption’.”
After falsifying paperwork and substituting microchips used to identify the horses, the animals were slaughtered and the meat shipped to Belgium.
The Civil Guard said that the profits from the illegal meat could reach €20m a year.
The case was linked to a 2013 scandal when Irish authorities detected beef burgers that contained horse meat.
Authorities in Belgium, France, Italy, Portugal, Romania, Switzerland, Britain and Spain co-operated in the operation.
Horse DNA was discovered in frozen beef burgers sold in a number of British and Irish supermarkets in 2013.
Ten million burgers were taken off shelves and sales fell by 43pc.
As many as 13 European countries were implicated in the scandal.
A spokesman for the Civil Guard said officers launched a full-scale probe called Operation Gazel after detecting “atypical signs in the horse meat trade” last summer.
“The investigation revealed the existence of an organisation which acquired horses which were in bad condition and old and not apt for consumption and sacrificed them in two specific slaughter houses,” he said.
“Those animals came from Portugal and various places in the north of Spain.
“Although they were distributed in different ways, their meat was mainly prepared in an industrial plant and sent from there to Belgium, which is the European Union’s leading meat exporter.”
The Civil Guard tracked a Dutch businessman to a property on the Costa del Sol, where he led a discreet life.
“From there he maintained business interests in activities that he already controlled in northern Europe,” the representative said.
“This person managed this network from the shadows, using men of confidence in each of the territories in which it was present.”
The spokesman claimed that the organisation changed the identify of the horses by substituting their microchips or falsifying animal passports.
The suspects are facing an ongoing criminal investigation led by a court in the northern town of Ponferrada, in the Spanish province of León, into alleged animal cruelty, forgery, money laundering, membership of a criminal organisation and a crime against public health.
A spokesman said: “As a result of the police operations, several bank accounts and properties have been embargoed and five recently-purchased high-end vehicles seized.”