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

Great-WestMultiMgrLgCapGrowIns (MXGSX Quick QuoteMXGSX - Free Report) has a 0.65% expense ratio and 0.62% management fee. MXGSX 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. With yearly returns of 14.04% over the last five years, this fund clearly wins.

T. Rowe Price Science & Technology Fund (PRSCX Quick QuotePRSCX - Free Report) . Expense ratio: 0.84%. Management fee: 0.63%. With a much more diversified approach, PRSCX--part of the Sector - Tech mutual fund category--gives investors a way to own a stake in the notoriously risky tech sector. This fund has managed to produce a robust 10.03% over the last five years.

TIAA-CREF Socl Choice Equity Institutional (TISCX Quick QuoteTISCX - Free Report) . Expense ratio: 0.17%. Management fee: 0.15%. Five year annual return: 10.46%. TISCX is a Large Cap Blend fund, targeting companies with market caps of over $10 billion. These funds offer investors a stability, and are perfect for people 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.