Personal Returns (T1) 
There are numerous dates throughout the year that must be observed to ensure that you don't miss a payment or filing deadline. There are often penalties as well as interest owed should a payment be late or a filing date missed. Following are the important dates that a taxpayer should be aware of. 

January 15 
Source deductions for wages and director's fees, which were paid in December, must be received by Canada Customs and Revenue Agency by January 15th. Whenever such wages or fees are paid throughout the year, the deductions must be remitted by the 15th of the following month. 

February 28 
T4's (director's fees, bonuses, wages paid etc.) and T5's must be filed for the previous calendar year. These must be postmarked no later than February 28th. 

March 15 
First installment of personal income tax is due. 

April 30
Personal (T1) tax returns must be filed and postmarked no later than April 30th. Returns for the taxpayer died in November or December of the prior year are due six months from the date of the death. 

June 15 
Second installment of personal income tax is due. If you are a taxpayer with sole proprietorship or partnership, income tax return can be filed until June 15th. However if there is a tax owing this must be paid by April 30th to avoid interest and penalty. 

September 15
Third installment of personal income tax is due.

December 15
Fourth installment of personal income tax is due.

Corporate Returns (T2)
Corporations have different set of deadlines and must follow the below guidelines :

• Corporation’s year end for tax purposes is their fiscal year end.
• All corporations must file tax return within six months of their fiscal year end.
• Public corporations must remit any amount due within two months of their year end.
• Corporations claiming small business deduction must remit any amount due with in three months of their year end.