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 take a look at some of our top-ranked mutual funds with the lowest fees.

Dreyfus Strategic Value Y (DRGYX Quick QuoteDRGYX - Free Report) : 0.63% expense ratio and 0.6% management fee. DRGYX is a part of the Large Cap Value category, and invests in equities with a market capitalization of $10 billion or more, but whose share prices do not reflect their intrinsic value. DRGYX has achieved five-year annual returns of an astounding 12.26%.

Fidelity Advisor Semiconductors M (FELTX Quick QuoteFELTX - Free Report) is a stand out amongst its peers. With a much more diversified approach, FELTX--part of the Sector - Tech mutual fund category--gives investors a way to own a stake in the notoriously risky tech sector. With five-year annualized performance of 28.11%, expense ratio of 1.25% and management fee of 0.53%, this diversified fund is an attractive buy with a strong history of performance.

MFS Mass Investors Growth Stock A (MIGFX Quick QuoteMIGFX - Free Report) is an attractive large-cap allocation. MIGFX 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. MIGFX has an expense ratio of 0.71%, management fee of 0.33%, and annual returns of 14.11% over the past five years.

These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a talk.