The funds in our "Magnificent Retirement Mutual Funds" list are among the best managed and best performing mutual funds available. If you are just finding out about our Top-Ranked Funds list, we welcome you!

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 break down some of the mutual funds with the highest Zacks Rank and the lowest fees.

Principal Mid Cap Growth J (PMGJX Quick QuotePMGJX - Free Report) has a 0.95% expense ratio and 0.65% management fee. PMGJX is a Mid Cap Growth mutual fund. These mutual funds choose companies with a stock market valuation between $2 billion and $10 billion. With yearly returns of 10.39% over the last five years, this fund clearly wins.

JPMorgan Small Cap Growth L (JISGX Quick QuoteJISGX - Free Report) is a stand out amongst its peers. JISGX is a Small Cap Growth mutual fund and tends to feature small companies in up-and-coming industries and markets. With five-year annualized performance of 14.33%, expense ratio of 0.84% and management fee of 0.65%, this diversified fund is an attractive buy with a strong history of performance.

T. Rowe Price Dividend Growth Adviser (TADGX Quick QuoteTADGX - Free Report) is an attractive large-cap allocation. TADGX is part of the Large Cap Blend section, and these mutual funds most often invest in firms with a market capitalization of $10 billion or more. By investing in bigger companies, these funds offer more stability, and are often well-suited for investors with a "buy and hold" mindset. TADGX has an expense ratio of 0.91%, management fee of 0.49%, and annual returns of 10.15% 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.