No, you do not need to file a separate return other than a Form 1040.  The TurboTax Self-Employed version will cover all your situation.  For a single member LLC, you will need to file a Schedule C to report your business income and expenses and a Schedule SE to pay self employment tax. As you enter the information in the program, it will create a Schedule C and SE.  Then the net profit from the Schedule C will be transferred to Form 1040 line 12 and the SE tax will be calculated and shown on line 27 and 57.