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

Fidelity Stock Selector Allocation Cap K (FSSKX Quick QuoteFSSKX - Free Report) : 0.57% expense ratio and 0.52% management fee. FSSKX 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. FSSKX has achieved five-year annual returns of an astounding 9.95%.

Deutsche Science and Technology Institutional (KTCIX Quick QuoteKTCIX - Free Report) : 0.69% expense ratio and 0.45% management fee. KTCIX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. With yearly returns of 13.99% over the last five years, KTCIX is an effectively diversified fund with a long reputation of solidly positive performance.

Putnam Multi-Cap Growth Fund A (PNOPX Quick QuotePNOPX - Free Report) : 0.92% expense ratio and 0.57% management fee. PNOPX is an All Cap Growth mutual fund with holdings across small, medium, and large-cap levels in order to increase diversification. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 10.91% over the last 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.