A post-closing trial balance is a list of balances of ledger accounts prepared after closing entries have been passed and posted to the ledger accounts. Since the closing entries transfer the balances of temporary accounts (i.e. expense, revenue, gain, dividend and withdrawal accounts) to the retained earnings account, the new balances of temporary accounts are zero and therefore they are not listed on a post-closing trial balance. However, all the other accounts having non-negative balances are listed including the retained earnings account.
The preparation of post-closing trial balance is the last step of the accounting cycle and its purpose is to be sure that sum of debits equal the sum of credits before the start of new accounting period. It provides the openings balances for the ledger accounts of the new accounting period.
The following post-closing trial balance was prepared after posting the closing entries of Company A to its general ledger and calculating new account balances:

Company A
Adjusted Trial Balance
January 31, 2010

 Particulars
Debit
Credit
Cash
20,430

Accounts Receivable
5,900

Office Supplies
4,320

Prepaid Rent
24,000

Equipment
80,000

Accumulated Depreciation

1,100
Accounts Payable

5,200
Utilities Payable

3,964
Unearned Revenue

1,000
Interest Payable

150
Notes Payable

20,000
Common Stock

100,000
Retained Earnings

3,236
Total
134,650
134,650
This is the end of the accounting cycle. In the next accounting period, the accounting cycle will be repeated again starting from the preparation of journal entries i.e. the first step of accounting cycle.