You need to file one tax return. You will enter the W-2 you receive from your full time employment. You will also need to enter the income you earned as a pet sitter as self-employment income (reported on Form 1040 Schedule C). You can deduct any expenses that you incurred that relate to pet sitting on the Schedule C.

You will need either the TurboTax Self-Employed (online) or Home & Business (CD/download) version to enter self-employment income.

Click here for information about TurboTax Self-Employed 

Click here for information about TurboTax Home & Business

To create a Schedule C for self-employment in TurboTax:

1.      Log on to TurboTax and pick up where you left off.

2.      Click the Search box in the right hand corner, search for "Schedule C", and click the first search result "Jump           to Schedule C".

3.      You will see the "Your self-employed work summary" screen. If you have entered a business into TurboTax               already, you will see it listed on this screen. (click on attachment below for a visual aid)

4.      Click Add another line of work (to create a new business in TurboTax) or click Edit (if you already added the               business into TurboTax)

5.      TurboTax will walk you through entering your income and expenses