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.

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

AQR Global Equity Fund N (AQGNX Quick QuoteAQGNX - Free Report) : 1.05% expense ratio and 0.6% management fee. AQGNX 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. AQGNX has achieved five-year annual returns of an astounding 10.47%.

Columbia Small Cap Value II Class R4 (CLURX Quick QuoteCLURX - Free Report) : 1.01% expense ratio and 0.83% management fee. CLURX is a Small Cap Value fund, and these funds are known for investing in companies with market caps under $2 billion. CLURX, with annual returns of 10.08% over the last five years, is a well-diversified fund with a long track record of success.

MFS Growth Fund I (MFEIX Quick QuoteMFEIX - Free Report) . Expense ratio: 0.59%. Management fee: 0.5%. Five year annual return: 15.69%. MFEIX 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.

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.