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.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

Let's learn about some of Zacks' highest ranked mutual funds with low fees you may want to consider.

Fidelity Advisor Technology M (FATEX Quick QuoteFATEX - Free Report) has a 1.22% expense ratio and 0.53% management fee. FATEX 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 24.88% over the last five years, this fund clearly wins.

Putnam Global Health Care R (PHSRX Quick QuotePHSRX - Free Report) : 1.32% expense ratio and 0.62% management fee. PHSRX is a Sector - Health mutual fund, which give investors an opportunity to focus on healthcare, one of the largest sectors of the American economy. PHSRX, with annual returns of 12.24% over the last five years, is a well-diversified fund with a long track record of success.

American Funds Mutual Fund R2E (RMEBX Quick QuoteRMEBX - Free Report) : 1.07% expense ratio and 0.23% management fee. RMEBX is a Large Cap Value fund. These funds invest in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 9.24% over the last five years.

We hope that your investment advisor (if you use one) has you invested in one or all of the top-ranked mutual funds we've reviewed. But if that isn't the case, it might be time to have a conversation or reconsider this vitally important relationship.