Will the IRS allow me to make a contribution to both a SEP-IRA and a Roth IRA?
The answer to your question is "Yes", a taxpayer may make a contribution to a SEP-IRA and a Roth IRA. However, the tax code specifically prohibits a taxpayer from making a SEP IRA contribution and Roth IRA contribution in the same account.
Clearly, the taxpayer should ensure that he meets the eligibility requirements to contribute to both the retirement plans.
An indepth discussion on this subject is available in IRS Publication 590, Individual Retirement Arrangements (IRAs), where the taxpayer can ascertain the eligibility requirements for both the SEP IRA and Roth IRA.