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.

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

If you are looking to diversify your portfolio, consider Goldman Sachs Large Cap Value A (GSLAX). GSLAX 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. This fund is a winner, boasting an expense ratio of 1%, management fee of 0.75%, and a five-year annualized return track record of 11.56%.

Boston Partners Global Equity Institutional (BPGIX Quick QuoteBPGIX - Free Report) : 0.95% expense ratio and 0.9% management fee. BPGIX 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 BPGIX, with annual returns of 13.36% over the last five years, is a well-diversified fund with a long track record of success.

Columbia Seligman Global Technology Z (CSGZX). Expense ratio: 1%. Management fee: 0.91%. Five year annual return: 23.33%. With a much more diversified approach, CSGZX--part of the Sector - Tech mutual fund category--gives investors a way to own a stake in the notoriously risky tech sector.

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.