The following is a list of important dates for the Osceola County Property Appraiser's Office.

• July 1, 2010: Preliminary Tax Roll due to Department of Revenue
• August 2010: Proposed Property Tax Notices “TRIM” mailed
• September 10, 2010: Petition filing deadline
• October 19-22, 2010: Value Adjustment Board Hearings
• March 1, 2011: Ag renewals cards (green cards) due
• March 1, 2011: Total permanent and total exempt renewal cards (gold cards) due
• March 1, 2011: Deadline for filing for Homestead
• April 1, 2011: Deadline for filing the Tangible Tax Return without penalty

The Property Appraiser follows an annual calendar of events established by Florida Law. The following are important dates in the annual process of preparing the Tax Roll:

• All Year: May pre-file for exemptions and classifications for the following year.
• January 1: Assessments are based on the status of the property on this date each year. This is also the effective date for establishing the validity of exemptions and agricultural classification applications.
• March 1: This is the deadline for filing Homestead Exemption, Seniors Exemption, Disability Exemption, various other exemptions, portability transfer and Agriculture Classification for the current tax year.
• March 2 Through the End of TRIM Period: Late filing of Homestead, with filing a petition to the Value Adjustment Board ($15.00 fee) and hardship reason for having missed the March 1st deadline.
• April 1: This is the deadline for filing Tangible Personal Property returns (DR-405) with the Property Appraiser’s office without incurring a penalty.
• After April 1 or Any Extension Period: Penalty for improper or late filing or failure to file Tangible Personal Property return (DR – 405).
• April 1 - June 30: Property Appraiser must notify applicant for exemption or classification IF DENIED.
• July 1: Property Appraiser submits a preliminary tax roll to the Department of Revenue for review and approval.
• August: Property Appraiser mails "TRIM" notice (Notice of Proposed Property Taxes) to all property owners. This notice is a review of the tax roll and contains your ASSESSED VALUE, as well as information on exemptions, millage rates, taxes, and hearing dates.
• August - September: 25 day period, starting with mailing of notices, in which you may discuss your value with the Property Appraiser’s staff, or discuss government spending with the taxing authorities. Dates of Public Hearings on budgets (taxes) are on the TRIM notice. LAST DAY TO FILE PROTEST OF VALUATION is contained in the TRIM notice also. It is difficult to reduce assessments after this date.
• Late September - Early October: VALUE ADJUSTMENT BOARD meets to review challenges to the Appraiser’s assessed value and denials for an exemption or agricultural classification. You must pay a filing fee ($15.00) and complete a petition form, which MUST BE FILED BY THE DEADLINE stated on the TRIM with the Clerk of the Board.
• October: The tax roll is certified to the Tax Collector. It is ALMOST IMPOSSIBLE to change assessments after this date.
• 60 Days After Tax Roll Certification: Last day to file suit in Circuit Court to protest an assessment or exemption decision.