The ratio between the amount of mortgage loans and the value of housing (the loan to value ratio) is a useful indicator for studying the financial situation of households. Two main price indicators are used to measure loan to value ratios for housing in Spain at the time of purchase: the transaction price recorded at the Property Registry and the appraisal value. Having generated a sample in which both price indicators refer to the same set of housing, the median loan to value ratio between 2004 and 2007 is found to stand between 70%, when the appraisal value is used, and 107%, when the transaction price is used. The difference between these two ratios narrowed from 2010, with the loan to value ratio using the appraisal value remaining at around 70%, while the ratio based on the transaction value fell to 80%. The Spanish Survey of Household Finances (EFF), conducted by the Banco de Espana, is an alternative data source, allowing a loan to value ratio to be obtained directly from households’ responses. This ratio, based on EFF data, has evolved in a similar way to the one derived from the transaction prices recorded at the Property Registry.