The average ratio between house prices and rents is an indicator of housing market conditions. Since micro data on rents are difficult to find, little is known about this ratio at the individual-property level. In this project, I analyse a real estate agency's proprietary dataset containing tens of thousands of rental transactions in Central London during the 2006-2012 period. I merge it with the Land Registry and isolate 1,922 properties which were both sold and rented out within a six-month period. I measure their price-rent ratios and show that price-rent ratios are higher for bigger and more central units.