It is never too late to invest in mutual funds for retirement. As such, if you plan to invest in some of the best funds, the Zacks Mutual Fund Rank can provide you with valuable guidance.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

Let's take a look at some of our top-ranked mutual funds with the lowest fees.

If you are looking to diversify your portfolio, consider

Wells Fargo Disciplined US Core A

(EVSAX Quick QuoteEVSAX - Free Report) . EVSAX 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. This fund is a winner, boasting an expense ratio of 0.84%, management fee of 0.35%, and a five-year annualized return track record of 16.21%.

Janus Henderson Research A

(JRAAX Quick QuoteJRAAX - Free Report) : 0.83% expense ratio and 0.48% management fee. JRAAX is a Large Cap Growth mutual fund, and these funds invest in many large U.S. firms that are projected to grow at a faster rate than their large-cap peers. With yearly returns of 16.8% over the last five years, JRAAX is an effectively diversified fund with a long reputation of solidly positive performance.

T. Rowe Price Value Fund

(TRVLX Quick QuoteTRVLX - Free Report) : 0.71% expense ratio and 0.56% management fee. TRVLX is a Large Cap Value fund. These funds invest in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. With a five-year annual return of 12.35%, this fund is a well-diversified fund with a long track record of success.

These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a talk.