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 best way to shortlist great mutual funds is to ensure solid performance, diversification, and low fees. Some are better than others, but utilizing the Zacks Mutual Fund Rank, we have identified three mutual funds that could be solid additions to one's retirement portfolio.

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

Principal Strategic Asset Management Conservative Growth J (PCGJX Quick QuotePCGJX - Free Report) : 0.44% expense ratio and 0.28% management fee. PCGJX is classified as an Allocation Balanced fund, which seeks to invest in a balance of asset types, like stocks, bonds, and cash, and including precious metals or commodities is not unusual. With annual returns of 10.23% over the last five years, this fund is a winner.

T. Rowe Price Value I (TRPIX): 0.57% expense ratio and 0.55% management fee. TRPIX is a Large Cap Value mutual fund, which invests in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. With yearly returns of 13.98% over the last five years, TRPIX is an effectively diversified fund with a long reputation of solidly positive performance.

AQR Small Cap Multi-Style R6 (QSERX): 0.52% expense ratio and 0.45% management fee. QSERX is a Small Cap Blend mutual fund, allowing investors a way to diversify their funds among various types of small-cap stocks. With a five-year annual return of 14.23%, 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.