Investing in mutual funds for retirement is never too late. And the Zacks Mutual Fund Rank can be an excellent tool for investors looking to invest in the best funds.

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.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

Oberweis Micro Cap Portfolio (OBMCX): 1.46% expense ratio and 1% management fee. OBMCX is a Small Cap Growth mutual fund and tends to feature small companies in up-and-coming industries and markets. OBMCX has achieved five-year annual returns of an astounding 18.07%.

Fidelity Pacific Basin (FPBFX): 0.98% expense ratio and 0.93% management fee. FPBFX is a Pacific Rim - Equity mutual fund; these funds typically invest in companies throughout the dominant export-focused markets of Hong Kong, Singapore, Taiwan, and Korea. With yearly returns of 10.15% over the last five years, FPBFX is an effectively diversified fund with a long reputation of solidly positive performance.

MFS Blended Research Intl Eq R3 (BRXTX Quick QuoteBRXTX - Free Report) . Expense ratio: 0.75%. Management fee: 0.35%. Five year annual return: 12.8%. BRXTX is a Non US - Equity option, focusing their investments acoss emerging and developed markets, and can often extend across cap levels too.

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.