Can I write off all my gambling losses? I don't win much, but I love playing the slots!

Did they put the winning amount in box 7 on the 1099-MISC? If so, in that case, they must think that you are a professional gambler. You have to file a Schedule C because gambling is your business. If so, I think that you get to deduct gambling losses as business expenses?

I don't know why they would have issued a 1099-MISC instead of W-2g; unless the winning didn't meet the criteria for issuing a W-2G.

However, I would treat the winnings and losses just as if it were a W-2G.  Losses are itemized.

I would be very careful about trying to file a Sch C as a professional gambler.  The standard to file in that status is very high, and would definitely create a red flag for audit.

This is a Supreme Court Case that lays out some of the criteria in which the Court found taxpayer to be a professional gambler. 

COMMISSIONER OF INTERNAL REVENUE, Petitioner v. Robert P. GROETZINGER

https://www.law.cornell.edu/supremecourt/text/480/23

Gambling income on a 1099-MISC should end up being reported on Line 21 of Form 1040.  In TurboTax, enter the 1099-MISC information.  If you are not in the professional gambling business, then you should not do a Schedule C.   It would be nice if the income was reported in Box 3, but even if reported in Box 7, you should not have to do a Schedule C if you are not in the "business" of gambling.  If they reported the income in Box 7, be sure to click the radio button that the income did not involve work like your main job.  And also click the radio button that "it didn't involve an intent to earn money."  (If you were not professional gambler, then you were likely playing a game to win money as opposed to having a job to "earn" money.)  This button is important to directly throw the income out of Schedule C and throw the income directly into Line 21 of Form 1040 where is likely belongs.  Losses can be deducted on Schedule A Line 28 as miscellaneous deductions that are not subject to the 2% limitation.  But if you are not itemizing and are getting the standard deduction, then the losses will not have a benefit.

With regard to deducting losses, I forgot to say that losses are not allowed to exceed the reported winnings.