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, 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.

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

Blue Current Global Dividend Instl (BCGDX Quick QuoteBCGDX - Free Report) : 1.01% expense ratio and 0.99% management fee. BCGDX is a Global - Equity mutual fund. These funds invest in large markets like the U.S., Europe, and Japan, and operate with very few geographical limitations With annual returns of 14.24% over the last five years, this fund is a winner.

T. Rowe Price Communications & Technology Fund (PRMTX): 0.77% expense ratio and 0.63% management fee. With a much more diversified approach, PRMTX--part of the Sector - Tech mutual fund category--gives investors a way to own a stake in the notoriously risky tech sector. With yearly returns of 8.31% over the last five years, PRMTX is an effectively diversified fund with a long reputation of solidly positive performance.

AQR Small Cap Multi-Style N (QSMNX): 0.87% expense ratio and 0.45% management fee. QSMNX is a Small Cap Blend mutual fund, and usually targets stocks with market caps of less than $2 billion, letting investors diversify their funds among other kinds of small-cap equities. With a five-year annual return of 14.52%, this fund is a well-diversified fund with a long track record of success.

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.