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.

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

American Century Investments Focused Dynamic Growth Investor (ACFOX Quick QuoteACFOX - Free Report) : 0.86% expense ratio and 0.85% management fee. ACFOX 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. With annual returns of 11.7% over the last five years, this fund is a winner.

Fidelity Select Software & IT Services (FSCSX Quick QuoteFSCSX - Free Report) . Expense ratio: 0.68%. Management fee: 0.52%. FSCSX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. This fund has managed to produce a robust 12.04% over the last five years.

JPMorgan US Equity Fund R6 (JUEMX Quick QuoteJUEMX - Free Report) . Expense ratio: 0.44%. Management fee: 0.4%. Five year annual return: 10.58%. JUEMX 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.

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.