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 Select Technology (FSPTX Quick QuoteFSPTX - Free Report) has a 0.67% expense ratio and 0.52% management fee. FSPTX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. With yearly returns of 12.31% over the last five years, this fund clearly wins.

JPMorgan Large Cap Growth I (SEEGX Quick QuoteSEEGX - Free Report) is a stand out amongst its peers. SEEGX 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 15.17%, expense ratio of 0.69% and management fee of 0.45%, this diversified fund is an attractive buy with a strong history of performance.

T. Rowe Price New Horizons I (PRJIX Quick QuotePRJIX - Free Report) . Expense ratio: 0.65%. Management fee: 0.63%. Five year annual return: 11.17%. PRJIX is a Small Cap Growth mutual fund building their portfolio around stocks with market caps under $2 billion and large growth opportunities.

These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a talk.