If I opened a Roth IRA with my former employer's pension check, would it be considered taxable income?

Dawn,

Assets from a pension plan cannot be deposited to a Roth IRA. This would be an excess contribution to the Roth IRA.

To deposit assets from a pension plan to a Roth IRA, the assets must first be deposited to a traditional IRA (including a SEP IRA). Of course, the assets must be rollover-eligible.

Then it would be converted (moved as a Roth IRA conversion) from the traditional IRA to the Roth IRA. At this point, it would be taxable.

I think you are asking is a pension check considered earned income. Answer is no. However, if you pick up a part time job which gives you a paycheck you become eligible.