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.

Dreyfus Strategic Value Y (DRGYX Quick QuoteDRGYX - Free Report) : 0.64% expense ratio and 0.6% management fee. DRGYX 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 annual returns of 11.27% over the last five years, this fund is a winner.

Fidelity OTC Portfolio K (FOCKX Quick QuoteFOCKX - Free Report) . Expense ratio: 0.69%. Management fee: 0.64%. FOCKX 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 14.13% over the last five years.

State Street Institutional US Equity Services (SUSSX Quick QuoteSUSSX - Free Report) . Expense ratio: 0.65%. Management fee: 0.37%. Five year annual return: 11.75%. SUSSX 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.

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.