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.

Cambiar SMID Fund Investor (CAMMX Quick QuoteCAMMX - Free Report) : 0.92% expense ratio and 0.8% management fee. CAMMX is a Mid Cap Value fund, which usually invests in companies with a stock market valuation between $2 billion and $10 billion. With annual returns of 11.38% over the last five years, this fund is a winner.

Dreyfus Fund (DREVX Quick QuoteDREVX - Free Report) is a stand out amongst its peers. DREVX 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 five-year annualized performance of 11.39%, expense ratio of 0.71% and management fee of 0.65%, this diversified fund is an attractive buy with a strong history of performance.

Fidelity Advisor Semiconductors A (FELAX Quick QuoteFELAX - Free Report) : 1.01% expense ratio and 0.52% management fee. FELAX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 20.51% over the last five years.

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.