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.

Let's break down some of the mutual funds with the top Zacks Mutual Fund Rank and the lowest fees.

Franklin Small-Mid Cap Growth R (FSMRX Quick QuoteFSMRX - Free Report) : 1.1% expense ratio and 0.46% management fee. FSMRX is a Small Cap Growth mutual fund and tends to feature small companies in up-and-coming industries and markets. With annual returns of 10.84% over the last five years, this fund is a winner.

JHancock Strategic Growth A (JSGAX Quick QuoteJSGAX - Free Report) . Expense ratio: 0.99%. Management fee: 0.56%. JSGAX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks. This fund has managed to produce a robust 15.88% over the last five years.

TIAA-CREF Small Cap Equity Institutional (TISEX Quick QuoteTISEX - Free Report) is an attractive large-cap allocation. TISEX is a Small Cap Blend mutual fund, and usually targets stocks with market caps of less than $2 billion, letting investors diversify their funds among other kinds of small-cap equities. TISEX has an expense ratio of 0.42%, management fee of 0.4%, and annual returns of 9.05% over the past 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.