There is never a wrong time to invest in mutual funds for retirement. So, if you're still looking for the best mutual funds, the Zacks Mutual Fund Rank can be a great guide.

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.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

MassMutual Premier Small/Mid Cap Opportunities R5 (MSCDX Quick QuoteMSCDX - Free Report) : 0.76% expense ratio and 0.58% management fee. MSCDX is a Small Cap Blend mutual fund, allowing investors a way to diversify their funds among various types of small-cap stocks. With annual returns of 12.1% over the last five years, this fund is a winner.

Oppenheimer Discovery I (ODIIX Quick QuoteODIIX - Free Report) . Expense ratio: 0.67%. Management fee: 0.6%. ODIIX is a Small Cap Growth mutual fund and tends to feature small companies in up-and-coming industries and markets. This fund has managed to produce a robust 12.31% over the last five years.

TIAA-CREF Large Cap Growth Retail (TIRTX Quick QuoteTIRTX - Free Report) : 0.68% expense ratio and 0.4% management fee. TIRTX 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 a five-year annual return of 15.92%, this fund is a well-diversified fund with a long track record of success.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.