Can I declare bankruptcy if I am not legally divorced yet?

Yes, you can file bankruptcy without your spouse regardless of whether or not a divorce is contemplated.  Whether you have to include your spouse's income, expenses, assets and debts in the paperwork and eligibility analyses depends in part on the laws of your state and whether or not you are separated or still living together. A competent and experienced bankruptcy lawyer in your area will be able to answer those questions for you. Mark Markus has been practicing exclusively bankruptcy law in California since 1991.  He is a Certified Specialist in Bankruptcy Law by the State Bar of California Board of Legal Specialization,  AV-Rated by martindale.com, and A+ rated by the Better Business Bureau.