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.

Putnam Small Cap Growth Y (PSYGX): 0.86% expense ratio and 0.67% management fee. PSYGX is a Small Cap Growth mutual fund and tends to feature small companies in up-and-coming industries and markets. With annual returns of 6.68% over the last five years, this fund is a winner.

Fidelity Advisor Diversified Stock O (FDESX Quick QuoteFDESX - Free Report) is a stand out amongst its peers. FDESX 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 12.68%, expense ratio of 0.41% and management fee of 0.4%, this diversified fund is an attractive buy with a strong history of performance.

Victory Global Equity Income (UGEIX): 1.02% expense ratio and 0.52% management fee. UGEIX is a Global - Equity mutual fund. These funds invest in large markets like the U.S., Europe, and Japan, and operate with very few geographical limitations With a five-year annual return of 13.49%, this fund is a well-diversified fund with a long track record of success.

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.