I have rental property that I have not been able to rent since may 2014. can I write off the loss of rental income? if so, how?

In short, your rental losses will be useless without offsetting passive income. rental losses are always classified as "passive losses" for tax purposes UNLESS you are a real estate pro. This greatly limits your ability to deduct them because passive losses can only be used to offset your passive income. They can't be deducted from ordinary/regular income you earn from a job or investments such wages self employer income commissionor etc.Passive income is the income you earn from rental real estate or other passive activities. An activity other than real estate is considered passive Passive income does not include income from a job, a business you actively manage, or investment income. Thus, for example, you'd have passive income if you earn a profit from one or more rentals.Without passive income, your rental losses become suspended losses you can't deduct until you have sufficient passive income in a future year or sell the property to an unrelated party. You may not be able to deduct such losses for years.