If you're invested in any of the funds in our "Magnificent Retirement Mutual Funds" list, congratulations on owning some of the best managed and top-performing mutual funds. If you are lucky enough to discover our list of Top-Ranked Funds for the first time, it's never too late to start investing with the best, especially when it comes to your retirement.

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.

Here are the funds that have achieved the #1 (Strong Buy) Zacks Rank and have low fees.

T. Rowe Price New America Growth Adviser (PAWAX Quick QuotePAWAX - Free Report) has a 1.05% expense ratio and 0.64% management fee. PAWAX is a part of the Large Cap Growth mutual fund category, which invest in many large U.S. companies that are expected to grow much faster compared to other large-cap stocks. With yearly returns of 10.29% over the last five years, this fund clearly wins.

MSIF International Advantage I (MFAIX Quick QuoteMFAIX - Free Report) : 0.98% expense ratio and 0.78% management fee. MFAIX is a Global - Equity mutual fund investing in bigger markets like the U.S., Europe, and Japan; these kinds of funds aren't limited by geography. With yearly returns of 10.19% over the last five years, MFAIX is an effectively diversified fund with a long reputation of solidly positive performance.

Red Oak Technology Select (ROGSX Quick QuoteROGSX - Free Report) is an attractive large-cap allocation. ROGSX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. ROGSX has an expense ratio of 0.95%, management fee of 0.74%, and annual returns of 14.13% over the past five years.

We hope that your investment advisor (if you use one) has you invested in one or all of the top-ranked mutual funds we've reviewed. But if that isn't the case, it might be time to have a conversation or reconsider this vitally important relationship.

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.