About 1,000 animal rights campaigners have marched peacefully through the streets of Oxford to mark World Day for Laboratory Animals.
The demonstration was also in protest against the building of a new £20m Oxford University laboratory complex on South Parks Road.
Police said they met with the protest organisers, Speak, for several talks in the weeks leading up to the event.
No arrests were made. Previous protests in Oxford have been marred by violence.
A Thames Valley Police spokesman thanked the public for its patience over the protest, which began in Broad Street at midday.
Asst Chief Constable Francis Habgood, who oversaw the police operation, said: "The policing operation was able to work alongside the organisers of the demonstration to ensure the group achieved their right to lawful protest without causing any major problems for the rest of the city."
In January, five people were arrested when violence broke out at a similar march.
The arrests were for public order offences, after fences were pushed down and missiles thrown.