The site - built and tailored to meet the needs of Spanish language households in the US - is the seventh addition to the Apartments.com network which comprises Apartment Finder, Apartment Home Living, move.com, doorsteps.com and realtor.com.
Apartmentos.com features high rises, condos and single family homes with an aim to help searchers find apartments through 3D interactive tours and comprehensive neighborhood content.
Founder and CEO of CoStar Group Andrew Florance said he hoped Apartamentos would be a welcome addition to the company's portfolio.
"We are excited to introduce our innovations to the Spanish-speaking community which represents a rapidly growing 20 percent of the renter population," he said.
"Apartments.com is just now celebrating its second anniversary of the site re-launch centered on enhancing the renter's experience. We have been very pleased with the profound response. We have delivered more than 57 million leads to advertisers," he said. We make the rental process easier for consumers by offering one site with complete and accurate inventory and comprehensive information."