If you have an existing ABN when you become bankrupt, the trustee will advise the Deputy Commissioner of Taxation of your bankruptcy. The Tax Office will note the date of your bankruptcy against the ABN. If you wish to continue to use the ABN you will need to contact the Tax Office and arrange to have your ABN reactivated. Regardless of Bankruptcy you will still be responsible for lodging your BAS Statement. There is no restriction on applying for an ABN after becoming a bankrupt.