Investing in mutual funds for retirement is never too late. And the Zacks Mutual Fund Rank can be an excellent tool for investors looking to invest in the best funds.

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 investors' portfolios.

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

T. Rowe Price Large Cap Growth Inv (TRGOX): 0.7% expense ratio and 0.54% management fee. TRGOX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks. TRGOX has achieved five-year annual returns of an astounding 12.3%.

Fidelity Growth & Income Portfolio K (FGIKX Quick QuoteFGIKX - Free Report) : 0.46% expense ratio and 0.45% management fee. FGIKX 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. With yearly returns of 16.16% over the last five years, FGIKX is an effectively diversified fund with a long reputation of solidly positive performance.

Morgan Stanley Global Permanence I (MGKIX): 1% expense ratio and 0.8% management fee. MGKIX is a Global - Equity mutual fund. These funds invest in large markets like the U.S., Europe, and Japan, and operate with very few geographical limitations With a five-year annual return of 10.43%, this fund is a well-diversified fund with a long track record of success.

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.