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.

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 learn about some of Zacks' highest ranked mutual funds with low fees you may want to consider.

American Century Small Cap Value A (ACSCX Quick QuoteACSCX - Free Report) : 1.34% expense ratio and 1.08% management fee. ACSCX is a Small Cap Value mutual fund, investing in small companies with stock market valuation less than $2 billion. ACSCX has achieved five-year annual returns of an astounding 10.05%.

Buffalo International Fund (BUFIX Quick QuoteBUFIX - Free Report) : 1.02% expense ratio and 0.85% management fee. BUFIX is a Non US - Equity fund. Many of these funds like to allocate across emerging and developed markets, and will often focus on all cap levels. BUFIX, with annual returns of 9.43% over the last five years, is a well-diversified fund with a long track record of success.

Shelton Equity Income Direct (EQTIX Quick QuoteEQTIX - Free Report) : 0.69% expense ratio and 0.45% management fee. EQTIX 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 10.9%, 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.