Staff at the Paolo Memorial Hospital Chokchai 4 dressed the babies in blue and brown crochet hats with dog ears and matching outfits for a photoshoot.
Parents were later given framed photos as a memento, said nurse Pilaiporn Kondee.
She said some parents specifically chose to give birth at the hospital because of the new year costumes and photo souvenirs on offer.
Nopparat Yodsaksee, 32, watched proudly as his newborn son posed for photos.
“This year is the most special year for our family so far,” Nopparat told Reuters.
“It’s something that has a lot of meaning.”
Twelve animals make up the traditional Chinese zodiac, with each year having its own unique beliefs. The Year of the Dog begins in February.