Mr Weyergraf, formerly part of the senior management team at eBay, takes over from former chief executive and erento founder Chris Moeller, who will stay with the company as head of product development and technology.
The new CEO, who joins erento from online market research company Panelbiz, where he has been CEO since April 2007, will drive the company's international expansion - particularly in the UK and US.
"The potential of erento is immense," said Mr Weyergraf. "The idea of having a website where you can rent the entire spectrum of goods and services is as simple as it is ingenious. The challenge for us now is to build on our international businesses and put in place the strategy and structures that will ensure our continued growth as the leading online rental company worldwide."
Before working at Panelbiz, Mr Weyergraf worked in senior management at eBay, held several senior positions at publishing group Georg von Holtzbrinck and was a principal consultant at PricewaterhouseCoopers.
Alexander Samwer of the European Founders Fund, one of erento's key investors, said: "We are delighted with Oliver's appointment. He is a successful web entrepreneur with a great track record and he will make a massive contribution to the expansion of erento."
erento (www.erento.co.uk) is an online rental marketplace, bringing together businesses with products or services to rent to customers. The site has over 1.5 million items available for rent across 26 countries.