Wanganui SPCA Centre opened its doors to the public for the first time on Saturday.
Manager Danny Auger estimated about 300 people turned up to have a look through the London St premises.
"It went really well - we were pleased," he said. "There was a huge number coming in who had never been in the centre before."
The aim was to promote the organisation and its work.
"The day was to open up the doors to let people see behind the scenes and let people know that we have nothing to hide. People thought it was great that they were able to do that."