Research by Spain's National Statistics Institute predicts that Spain's immigrant population will rise to as much as 5.5 million by 2010, representing in the region of 12% of its population, compared to just 5% in 2001. The rising demand for property will continue to fuel the growth of the property market.
It's impossible to predict exactly what return you'll get from your investment but recent reports from various sources agree that it will be high. For example:
Property News reports that house prices on the Costa del Sol rose by more than 18.5% in 2002.
Spain's ministry of development has gone on record as saying that the average increase in Spanish house prices was 17.5 percent in the second quarter of 2003 compared to the same period in 2002.
Above information from Spanish-Property.ws