Our "Magnificent Retirement Mutual Funds" list includes some of the best managed and best performing funds around. If you're already invested in these, congratulations! But if you're just now discovering them, don't worry. When it comes to your retirement, it's never too late to start investing in the best.The easiest way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. Using our Zacks Rank of over 19,000 mutual funds, we've identified three outstanding mutual funds that are ideally suited to help long-term investors pursue and achieve their retirement investing goals.Let's take a look at some of the highest Zacks Ranked mutual funds with the lowest fees.Invesco Summit P (SMMIX): 0.85% expense ratio and 0.63% management fee. SMMIX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks. SMMIX has achieved five-year annual returns of an astounding 13.82%.Polen Global Growth Instl (PGIIX): 1.1% expense ratio and 0.85% management fee. PGIIX is a Global - Equity mutual fund. These funds invest in large markets like the U.S., Europe, and Japan, and operate with very few geographical limitations. With yearly returns of 14.89% over the last five years, PGIIX is an effectively diversified fund with a long reputation of solidly positive performance.Champlain Mid Cap Fund Institutional (CIPIX) is an attractive large-cap allocation. CIPIX is a Mid Cap Growth mutual fund. These funds aim to target companies with a market capitalization between $2 billion and $10 billion that are also expected to exhibit more extensive growth opportunities for investors than their peers. CIPIX has an expense ratio of 0.86%, management fee of 0.71%, and annual returns of 12.57% over the past five years.There you have it. If your financial advisor had you put your money into any of our "Magnificent Retirement Mutual Funds," then they've got you covered. If not, you may need to talk.Do You Know the Top 9 Retirement Investing Mistakes?Investing in underperforming mutual funds is just one of the key errors that can derail your retirement plans.To learn more, read our just-released report: 9 Retirement Mistakes You Need to Avoid.This report can help you sidestep these costly mistakes and potentially achieve your retirement goals. Get Your FREE Guide Now Get Your Free (CIPIX): Fund Analysis Report Get Your Free (SMMIX): Fund Analysis Report Get Your Free (PGIIX): Fund Analysis Report To read this article on Zacks.com click here. Zacks Investment Research