You can only use gambling losses to offset gambling winnings, nothing else, and only up to the amount of winnings, nothing more. And yes, you would be smart to combine business with pleasure (gambling) so that your plane fare, hotel rooms (if you don't have room comps), rental car, meals, etc, are deductible as business expenses. For some, however, it is next to impossible to keep their gambling from interfering with their business. In that case, keep your business and gambling trips separate. It's your call to make.