[jwasbury]

file returns in both states. state b will tax the income you earned there, and should tax nothing else. state a, your state of residency, will likely tax all your income (earned income and also investment income, if any). for state b you will probably need to file as "part year" or "non resident"which may be a different form than a resident files. there is usually a section where you can apportion your income between taxable (for the time you spent in state b) and non-taxable (for the time you telecommuted from home). state a will tax you on 100% of your income, but should allow a credit for the taxes you pay to state b - this is the way you avoid double taxation.