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.

How can you tell a good mutual fund from a bad one? It's pretty basic: if the fund is diversified, has low fees, and shows strong performance, it's a keeper. Of course, there's a wide range, but using the Zacks Mutual Fund Rank, we've found three mutual funds that would be great additions to any long-term retirement investors' portfolios.

Let's break down some of the mutual funds with the top Zacks Mutual Fund Rank and the lowest fees.

American Century Large Company Value R6

(ALVDX Quick QuoteALVDX - Free Report) : 0.49% expense ratio and 0.48% management fee. ALVDX is a Large Cap Value mutual fund, which invests in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. With annual returns of 10.41% over the last five years, this fund is a winner.

Fidelity New Millennium

(FMILX Quick QuoteFMILX - Free Report) : 0.8% expense ratio and 0.68% management fee. FMILX is an All Cap Growth mutual fund. In order to increase diversification, these funds have holdings across small, medium, and large-cap levels. With yearly returns of 16.76% over the last five years, FMILX is an effectively diversified fund with a long reputation of solidly positive performance.

ClearBridge Large Cap Growth I

(SBLYX Quick QuoteSBLYX - Free Report) is an attractive large-cap allocation. SBLYX 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. SBLYX has an expense ratio of 0.73%, management fee of 0.64%, and annual returns of 16.08% over the past five years.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.