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.

Fidelity OTC Portfolio (FOCPX Quick QuoteFOCPX - Free Report) : 0.78% expense ratio and 0.64% management fee. FOCPX 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 annual returns of 11.76% over the last five years, this fund is a winner.

JPMorgan US Equity Fund R5 (JUSRX Quick QuoteJUSRX - Free Report) is a stand out amongst its peers. JUSRX 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. With five-year annualized performance of 10.93%, expense ratio of 0.54% and management fee of 0.4%, this diversified fund is an attractive buy with a strong history of performance.

BlackRock Long-Horizon Equity I (MAEGX Quick QuoteMAEGX - Free Report) . Expense ratio: 0.95%. Management fee: 0.8%. Five year annual return: 10.08%. MAEGX is a Global - Equity mutual fund, which invests their assets in large markets, leveraging the global economy.

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.