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.

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.

Columbia Small Cap Value II Class R4 (CLURX Quick QuoteCLURX - Free Report) : 1.01% expense ratio and 0.83% management fee. CLURX is a Small Cap Value fund, and these funds are known for investing in companies with market caps under $2 billion. CLURX has achieved five-year annual returns of an astounding 8.12%.

JPMorgan Intrepid Growth Fund A (JIGAX Quick QuoteJIGAX - Free Report) is a stand out amongst its peers. JIGAX is a part of the Large Cap Growth mutual fund category, which invest in many large U.S. companies that are expected to grow much faster compared to other large-cap stocks. With five-year annualized performance of 14.82%, expense ratio of 0.84% and management fee of 0.3%, this diversified fund is an attractive buy with a strong history of performance.

AQR Small Cap Momentum Style N (ASMNX Quick QuoteASMNX - Free Report) : 0.86% expense ratio and 0.45% management fee. ASMNX is a Small Cap Growth mutual fund and tends to feature small companies in up-and-coming industries and markets. With a five-year annual return of 8.54%, 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.