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 easiest way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. Using the Zacks Mutual Fund Rank of over 19,000 mutual funds, we've identified three outstanding mutual funds that are ideally suited to help long-term investors pursue and achieve their retirement investing goals.

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

Fidelity Select Semiconductors (FSELX Quick QuoteFSELX - Free Report) : 0.68% expense ratio and 0.53% management fee. FSELX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. FSELX has achieved five-year annual returns of an astounding 35.82%.

American Funds Growth and Income Portfolio R5 (RGNFX Quick QuoteRGNFX - Free Report) : 0.06% expense ratio and 0% management fee. RGNFX 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. With yearly returns of 10.11% over the last five years, RGNFX is an effectively diversified fund with a long reputation of solidly positive performance.

Vanguard US Growth Admiral (VWUAX Quick QuoteVWUAX - Free Report) is an attractive large-cap allocation. VWUAX is a Large Cap Growth mutual fund, and these funds invest in many large U.S. firms that are projected to grow at a faster rate than their large-cap peers. VWUAX has an expense ratio of 0.2%, management fee of 0.19%, and annual returns of 15.1% 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.