Answer: The short answer is yes. You will want to check with your HSA administrator about how best to do that. Most administrators will accept checks. You will also want to ensure that you do not exceed the maximum annual contributions of $2,850 if you have an individual plan or $5,650 if you have a family plan. Additionally if you are over the age of 55 you can make catch-up contributions. For 2007 the maximum amount you can contribute is $800 as a catch-up contribution. You might find the US Treasury website helpful. Hope this helps.